Jaquelin P. Dudley
Video - PC Mac
|Education:||Ph.D.: 1978, Baylor College of Medicine|
|Postdoc.:||UC-San Francisco; University of Wisconsin|
|Research:||Transcription regulation and oncogenesis|
|Phone:||(512) 471-8415 Fax: (512) 471-7088|
The University of Texas at Austin
Molecular Genetics & Microbiology
1 University Station A5000
Austin TX 78712-0162
|Courses taught:||BIO 330 "Animal Virology"
BIO 391P "Advanced Virology"
Mouse mammary tumor virus (MMTV) is a retrovirus that induces mammary carcinomas in mice and also other tumors, particularly T-cell lymphomas. MMTV strains that cause T-cell lymphomas have a deletion of 350-500 bp at the ends of the viral genome (long terminal repeats or LTRs) compared to MMTV strains that cause mammary cancers. We have shown by molecular engineering experiments that we can completely switch the cancer-inducing ability of the virus from breast cancers to T-cell lymphomas. The LTR deletion found in lymphomagenic MMTVs removes the 3' end of the superantigen or sag gene that encodes the Sag protein. The Sag protein is involved in amplification of virus-infected lymphocytes that are necessary to transport virus from milk in the gut of newborn mice to the mammary gland. Some of our experiments have been directed toward understanding the role of the Sag protein in the MMTV life cycle and in tumorigenesis. The LTR deletions in lymphomagenic MMTVs also remove at least two negative regulatory elements (NREs) that are binding sites for cellular transcription factors. Two of these factors, special AT-rich sequence binding protein (SATB1) and CCAAT-displacement protein (CDP), bind to the MMTV NREs and have interesting tissue-specific distributions. SATB1 appears to have high expression in T cells, and loss of SATB1-binding sites in the MMTV LTR appears to be required to allow MMTV variants to cause lymphomas. Deletion of the NREs allows higher MMTV transcription and replication in T cells, leading to increased insertion of the viral genome near cellular proto-oncogenes, such as c-myc. Such integration events are necessary for MMTV-induced tumors. We also have shown that CDP is developmentally regulated in the mammary gland, so that MMTV and other mammary-specific genes are suppressed in virgin and pregnant mammary glands. Developmentally programmed disappearance of CDP during lactation allows virus expression to peak during the exact period where MMTV is transmitted from mothers to their pups through milk. Thus, MMTV has evolved an extremely tight system to regulate its expression in different tissues to optimize its transmission during lactation and minimize virus replication at other times. The study of MMTV promises to increase our understanding of tissue-specific gene regulation and tumorigenesis. Most recently, we have been developing MMTV as a vector system for gene therapy of breast cancer. In this process, we discovered a new viral protein, Rem, which is involved in the nuclear export of intron-containing viral mRNAs. These results are exciting because MMTV might be used as a mouse model for study of another retrovirus, human immunodeficiency virus (HIV), which causes AIDS.
Rorg (Rorc) is a common integration site in type B leukemogenic virus-induced T-cell lymphomas.
Broussard, D. R., M. M. Lozano, and J. P. Dudley (2004) Journal of Virology. 78:4943-4946.
The homeodomain protein CDP regulates mammary-specific gene transcription and tumorigenesis.
Zhu, Q., U. Maitra, D. Johnston, M. Lozano and J. P. Dudley. (2004) Molecular and Cellular Biology 24:4810-4823.
The type B leukemogenic virus truncated superantigen is dispensable for T-cell leukemogenesis.
Mustafa, F., S. Bhadra, D. Johnston, M. Lozano, and J. P. Dudley. (2003) Journal of Virology. 77:3866-3870.
Tag, you’re hit: retroviral insertions identify genes involved in cancer.
Dudley, J. P. (2003) Trends in Molecular Medicine. 9:43-45.
Binding of CCAAT displacement protein CDP to adenovirus packaging sequences.
Erturk, E., P. Ostapchuk, S. I. Wells, J. Yang, K. Gregg, A. Nepveu, J. P. Dudley, and P. Hearing.
(2003) Journal of Virology. 77:6255-6264.
Selection for c-myc integration sites in polyclonal T-cell lymphomas.
Broussard, D. R., J. A. Mertz, and J. P. Dudley.
Journal of Virology 76 (2002) pp. 2087-2099.
CDP binding to multiple sites in the MMTV LTR suppresses basal and glucocorticoid-induced transcription.
Zhu, Q. and J. P. Dudley.
Journal of Virology 76 (2002) pp. 2168-2179.
What retroviruses teach us about the involvement of c-myc in leukemias and lymphomas.
Dudley, J. P., J. A. Mertz, L. Rajan, M. Lozano, and D. R. Broussard.
Leukemia (2002), in press.
Type B leukemogenic virus has a T-cell-specific enhancer that binds AML-1.
Mertz, J. A., F. Mustafa, S. Meyers, and J. P. Dudley.
Journal of Virology 75 (2001) pp. 2174-2184.
A retroviral model for tissue-specific transcription: lessons for gene therapy.
Zhu, Q. and J. P. Dudley.
Journal of Gene Therapy and Molecular Biology 6 (2001) pp. 169-181.
C3H mouse mammary tumor virus (MMTV) superantigen function requires a splice donor site in the envelope gene.
Mustafa, F., M. Lozano, J.P. Dudley.
Journal of Virology 74 (2000) pp. 9431-9440.
Zhu Q, K. Gregg, M. Lozano, J. Liu, J.P. Dudley.
Journal of Virology 74 (2000): pp. 6348-57.
ABSTRACT: Mouse mammary tumor virus (MMTV) transcription is highest in the lactating mammary gland but is detectable in a variety of other tissues. Previous results have shown that MMTV expression is suppressed in lymphoid and other tissues through the binding of the homeodomain-containing repressor special AT-rich binding protein 1 to a negative regulatory element (NRE) in the MMTV long terminal repeat (LTR). Another homeoprotein repressor, CCAAT displacement protein (CDP), also binds to the MMTV NRE, but a role for CDP in MMTV transcriptional suppression has not yet been demonstrated. In this paper, we show that the level of CDP decreases during development of the mammary gland and that this decline in CDP level correlates with the known increase in MMTV expression observed during mammary gland differentiation. Moreover, CDP overexpression was able to suppress MMTV LTR-reporter gene activity up to 20-fold in transient-transfection assays of mouse mammary cells. To determine if this effect was due to direct binding of CDP to the promoter-proximal NRE, we performed DNase I protection assays to map two CDP-binding sites from +835 to +845 and +920 to +931 relative to the first base of the LTR. Mutations engineered into each of these sites decreased CDP binding to the proximal NRE, whereas a combination of these mutations further reduced binding. Subsequently, each of these mutations was introduced into the full-length MMTV LTR upstream of the luciferase reporter gene. Analysis of stable transfectants of LTR constructs showed that CDP binding site mutations in the proximal NRE elevated reporter gene expression two- to sixfold compared to wild-type LTR constructs. Thus, MMTV expression increases during mammary gland development, in part due to decreased CDP levels and CDP binding to the LTR. Together, these experiments provide the first evidence that CDP acts as a repressor of MMTV transcription in the mammary gland.The c-myc locus is a common integration site in type B retrovirus-induced T-cell lymphomas.
Rajan L, D. Broussard, M. Lozano, C.G. Lee, C.A. Kozak, J.P. Dudley
Journal of Virology 74 (2000): pp. 2466-71.
ABSTRACT: Type B leukemogenic virus (TBLV) induces rapidly appearing T-cell leukemias. TBLV insertions near the c-myc gene were detectable in 2 of 30 tumors tested, whereas 80% of the tumors showed c-myc overexpression. TBLV insertions on chromosome 15 (including a newly identified locus, Pad7) may cause c-myc overexpression by cis-acting effects at a distance.
Mouse mammary tumor virus.
Dudley, J. P.
in R. G. Webster and A. Granoff (ed.), Encyclopedia of Virology, Saunders Scientific Publications, London, 1999.
Barnett, A., T.J. Wrona, M. Lozano, F. Mustafa, and J.P. Dudley.
Journal of Virology 73 (1999): 6634-6645.
ABSTRACT: Mouse mammary tumor virus (MMTV) encodes a superantigen (Sag) that is expressed at the surface of antigen-presenting cells in conjunction with major histocompatibility complex (MHC) type II molecules. The Sag-MHC complex is recognized by entire subsets of T cells, leading to cytokine release and amplification of infected B and T cells that carry milk-borne MMTV to the mammary gland. Expression of Sag proteins from endogenous MMTV proviruses carried in the mouse germ line usually results in the deletion of self-reactive T cells during negative selection in the thymus and the elimination of T cells required for infection by specific milk-borne MMTVs. However, other endogenous MMTVs are unable to eliminate Sag-reactive T cells in newborn mice and cause partial loss of reactive T cells in adults. To investigate the kinetics of Sag-reactive T-cell deletion, backcross mice that contain single or multiple MMTVs were screened by a novel PCR assay designed to distinguish among highly related MMTV strains. Mice that contained Mtv-17 alone showed slow kinetics of reactive T-cell loss that involved the CD4(+), but not the CD8(+), subset. Deletion of CD4(+) or CD8(+) T cells reactive with Mtv-17 Sag was not detected in thymocytes. Slow kinetics of peripheral T-cell deletion by Mtv-17 Sag also was accompanied by failure to detect Mtv-17 sag-specific mRNA in the thymus, despite detectable expression in other tissues, such as spleen. Together, these data suggest that Mtv-17 Sag causes peripheral, rather than intrathymic, deletion of T cells. Interestingly, the Mtv-8 provirus caused partial deletion of CD4(+)Vbeta12(+) cells in the thymus, but other T-cell subsets appeared to be deleted only in the periphery. Our data have important implications for the level of antigen expression required for elimination of self-reactive T cells. Moreover, these experiments suggest that mice expressing endogenous MMTVs that lead to slow kinetics of T-cell deletion will be susceptible to infection by milk-borne MMTVs with the same Sag specificity.Homeoproteins CDP and SATB1 interact: potential for tissue-specific regulation.
Liu, J., A. Barnett, E.J. Neufeld, and J.P. Dudley
Molecular and Cellular Biology 19 (1999): 4918-4926.
ABSTRACT: Homeoproteins are known to participate in development and cell type specification. The homeoproteins CCAAT displacement protein (CDP) and special AT-rich sequence binding protein 1 (SATB1) have been shown to bind to nuclear matrix-associated regions and to act as repressors of many cellular genes. Moreover, binding of SATB1 to the mouse mammary tumor virus (MMTV) promoter region dramatically affects the tissue-specific transcription of this retrovirus. Because protein-protein interactions are a common means of regulating homeoprotein function, we tested whether SATB1 and CDP interact in vivo and in vitro. SATB1 interacted with CDP through its DNA-binding domain, as demonstrated by glutathione S-transferase (GST) pull-down assays. GST pull-down assays also showed that CDP associated with SATB1 through three of its four DNA-binding domains (CR1, CR2, and the homeodomain). SATB1-specific antisera, but not preimmune sera, precipitated CDP from nuclear extracts, and CDP-specific antisera precipitated SATB1 from the same extracts. Far-Western blotting detected interaction of SATB1 and CDP in several different tissue extracts. Association of purified SATB1 and CDP in vitro resulted in the inability of each protein to bind to DNA in gel retardation assays. CDP overexpression in cultured T cells led to a loss of detectable SATB1 binding to the MMTV promoter region, as measured by gel shift experiments. CDP overexpression also elevated MMTV long terminal repeat reporter gene activity in transient-transfection assays, a result consistent with neutralization of the SATB1 repressor function in T cells. SATB1 is very abundant in certain tissues, particularly thymus, whereas CDP is relatively ubiquitous, except in certain terminally differentiated cell types. Because of the tissue and cell type distribution of SATB1 and CDP, we propose that the SATB1-to-CDP ratio in different tissues is a novel mechanism for homeoproteins to control gene expression and differentiation in mammals.
Chromosomal localization of acquired mouse mammary tumor proviral integration sites in T-cell lymphomas.
Rajan, L., C. A. Kozak, and J. P. Dudley.
Mammalian Genome 9 (1998): 84-85.
Wrona, T. J., M. Lozano, A. A. Binhazim, and J. P. Dudley.
Journal of Virology 72 (1998): 4746-4755.
ABSTRACT: The mouse mammary tumor virus (MMTV) encodes within the U3 region of the long terminal repeat (LTR) a protein known as the superantigen (Sag). Sag is needed for the efficient transmission of milk-borne virus from the gut to target tissue in the mammary gland. MMTV-infected B cells in the gut express Sag as a type II transmembrane protein that is recognized by the variable region of particular beta chains (Vbeta) of the T-cell receptor (TCR) on the surface of T cells. Recognition of Sag by particular TCRs results in T-cell stimulation, release of cytokines, and amplification of MMTV infection in lymphoid cells that are needed for infection of adolescent mammary tissue. Because the C-terminal 30 to 40 amino acids of Sag are variable and correlate with recognition of particular TCR Vbeta chains, we prepared a series of C-terminal Sag mutations that were introduced into a cloned infectious MMTV provirus. Virus-producing XC rat cells were used for injection of susceptible BALB/c mice, and these mice were monitored for functional Sag activity by the deletion of C3H MMTV Sag-reactive (CD4+ Vbeta14+) T cells. Injected mice also were analyzed for mutant infection and tumor formation in mammary glands as well as milk-borne transmission of MMTV to offspring. Most mutations abrogated Sag function, although one mutation (HPA242) that changed the negative charge of the extreme C terminus to a positive charge created a weaker Sag that slowed the kinetics of Sag-mediated T-cell deletion. Despite the lack of Sag activity, many of the sag mutant viruses were capable of sporadic infections of the mammary glands of injected mice but not of offspring mice, indicating that functional Sag increases the probability of milk-borne MMTV infection. Furthermore, although most viruses encoding nonfunctional Sags were unable to cause mammary tumors, tumors were induced by such viruses carrying mutations in a negative regulatory element that overlaps the sag gene within the LTR, suggesting that loss of Sag function may be compensated, at least partially, by loss of transcriptional suppression in certain tissues. Together these results confirm the importance of Sag for efficient milk-borne transmission and indicate that the entire C-terminal region is needed for complete Sag function.
B and T cells are required for mouse mammary tumor virus spread within the mammary gland.
Golovkina, T. V., J. P. Dudley, and S. R. Ross.
The Journal of Immunology
ABSTRACT: Mouse mammary tumor virus (MMTV) is an infectious retrovirus transmitted through milk from mother to newborns. MMTV encodes a superantigen (SAg) whose activity is indispensable for the virus life cycle, since a genetically engineered virus with a mutation in the sag gene neither amplified in cells of the immune system of suckling pups nor infected their mammary glands. When wild-type MMTV was injected directly into the mammary glands of uninfected pubescent mice, their lymphoid as well as mammary gland cells became virus infected. To test whether this infection of lymphoid cells was dependent on SAg activity and required for virus spread within the mammary gland, we performed mammary gland injections of wild-type MMTV(C3H) into two strains of transgenic mice that lacked SAg-cognate, V beta 14+ T cells. Neither the MTV-ORF or LEL strains showed infection of their mammary glands. Moreover, no MMTV infection of their peripheral lymphocytes was detected. Similar experiments with mice lacking B cells (mu-chain knockouts) showed no detectable virus spread in the mammary glands or lymphoid tissues. These data suggest that SAg activity and MMTV-infected lymphocytes are required, not only for initial steps of viral infection, but also for virus spread within the mammary gland. Virus spread at late times in infection determines whether MMTV induces mammary tumors.
An MMTV integration site maps near the distal end of mouse Chromosome 11.
Rajan, L. and J. P. Dudley.
Mammalian Genome 8 (1997): 295-296.
Bramblett, D., J. Liu, M. Lozano, L. Xu, T. Wrona, L. Rajan, S. R. Ross and J. Dudley.
Leukemia 11 (1997): 183-186.
ABSTRACT: Mouse mammary tumor virus (MMTV) causes mammary carcinomas and T-cell tumors in mice. MMTV variants that induce T-cell tumors have a large deletion within the U3 region of the long terminal repeat (LTR) compared to MMTV strains that induce mammary tumors. We provide evidence here that T-cell tropic MMTV strains lack a redundant binding site for a cellular protein called NBP (negative regulatory element binding protein). The lack of NBP-binding sites in T-cell tropic MMTV strains presumably leads to higher levels of transcription in T-cells during the MMTV life cycle and an increased incidence of mutagenic integration events.The matrix attachment region-binding protein SATB1 participates in negative regulation of tissue-specific gene expression.
Liu, J., D. Bramblett, Q. Zhu, M. Lozano, R. Kobayashi, S. R. Ross, and J. P. Dudley.
Molecular and Cellular Biology 17 (1997): 5275-5287.
ABSTRACT: The nuclear matrix has been implicated in several cellular processes, including DNA replication, transcription, and RNA processing. In particular, transcriptional regulation is believed to be accomplished by binding of chromatin loops to the nuclear matrix and by the concentration of specific transcription factors near these matrix attachment regions (MARs). A number of MAR-binding proteins have been identified, but few have been directly linked to tissue-specific transcription. Recently, we have identified two cellular protein complexes (NBP and UBP) that bind to a region of the mouse mammary tumor virus (MMTV) long terminal repeat (LTR) previously shown to contain at least two negative regulatory elements (NREs) termed the promoter-proximal and promoter-distal NREs. These NREs are absent from MMTV strains that cause T-cell lymphomas instead of mammary carcinomas. We show here that NBP binds to a 22-bp sequence containing an imperfect inverted repeat in the promoter-proximal NRE. Previous data showed that a mutation (p924) within the inverted repeat elevated basal transcription from the MMTV promoter and destabilized the binding of NBP, but not UBP, to the proximal NRE. By using conventional and affinity methods to purify NBP from rat thymic nuclear extracts, we obtained a single major protein of 115 kDa that was identified by protease digestion and partial sequencing analysis as the nuclear matrix-binding protein special AT-rich sequence-binding protein 1 (SATB1). Antibody ablation, distamycin inhibition of binding, renaturation and competition experiments, and tissue distribution data all confirmed that the NBP complex contained SATB1. Similar types of experiments were used to show that the UBP complex contained the homeodomain protein Cux/CDP that binds the MAR of the intronic heavy-chain immunoglobulin enhancer. By using the p924 mutation within the MMTV LTR upstream of the chloramphenicol acetyltransferase gene, we generated two strains of transgenic mice that had a dramatic elevation of reporter gene expression in lymphoid tissues compared with reporter gene expression in mice expressing wild-type LTR constructs. Thus, the 924 mutation in the SATB1-binding site dramatically elevated MMTV transcription in lymphoid tissues. These results and the ability of the proximal NRE in the MMTV LTR to bind to the nuclear matrix clearly demonstrate the role of MAR-binding proteins in tissue-specific gene regulation and in MMTV-induced oncogenesis.Strain-specific expression of spliced MMTV RNAs containing the superantigen gene.
Xu, L., T. J. Wrona, and J. P. Dudley.
Virology 236 (1997): 54-65.
ABSTRACT: The transmission of milk-borne or exogenous mouse mammary tumor virus (MMTV) requires infection of B cells in the gut-associated lymphoid tissue and expression of the superantigen (Sag) protein at the B-cell surface. Presentation of Sag at the B-cell surface is required for the transmission of MMTV to T cells and subsequent infection of the target mammary gland tissue. Because several different promoters have been reported for MMTV sag mRNA expression, we investigated whether the detection of spliced sag RNAs was dependent upon the cell type infected or the particular MMTV strain examined. In this study, we detected expression of spliced sag RNA from the standard promoter and from an internal U3 promoter in B-cell lines expressing endogenous Mtv-6 by RT-PCR, although expression from the standard promoter appeared to be at least 10-fold higher than that observed from the internal U3 promoter. Sag RNA originating from exogenous C3H MMTV was not observed from either of the U3 promoters in any cell type examined. However, spliced mRNAs containing the exogenous C3H MMTV, endogenous Mtv-8, or endogenous Mtv-17 sag genes could be detected from a previously described promoter in the envelope coding region regardless of the cell type infected. Because sag-specific RNAs can be initiated independently of the LTR promoters, there may be selection for independent control of MMTV sag and structural gene expression.
Xu, L., T. J. Wrona, and J. P. Dudley.
Virology 215 (1996): 113-123.
ABSTRACT: The mouse mammary tumor virus (MMTV) superantigen (Sag) protein is involved in the transmission of milk-borne MMTV from virus-infected milk in the gut to the target mammary gland tissue. Using an RT-PCR assay for in vivo MMTV infection, BALB/c or C3H mice nursed on C3H MMTV-infected mothers showed sag mRNA expression in intestine, spleen, and thymus as early as 1 day after infection, whereas uninfected BALB/c control animals had approximately 10- to 30-fold lower sag expression. Further fractionation experiments with small intestine indicated that sag expression occurred in gut-associated lymphoid cells. Restriction enzyme digestion of PCR products indicated that the sag mRNA detected was derived from the endogenous MMTVs, and sequencing analysis confirmed that the PCR products were derived from endogenous MTv-6. Expression of C3H-specific mRNA was detectable in BALB/cfC3H or C3H tissues by RNase protection or by RT-PCR. Endogenous MMTV sag expression was low in spleen and undetectable in thymocytes of C3H MMTV-infected C57BL/6 mice, a strain resistant to C3H MMTV tumorigenesis and defective for MHC class II I-E molecules. The RT-PCR assay for sag mRNA appears to measure the Sag-induced stimulation previously predicted for milk-borne MMTV infection. Together these data suggest that exogenous MMTV sag expression is minimal, but sufficient to rapidly stimulate transcription of endogenous MMTV sag mRNA in B- and T-cells in an MHC class II I-E-dependent manner. The endogenous sag expression on maternal lymphocytes may increase the number of proliferating T-cells available for milk-borne MMTV infection.Major histocompatibility complex class II I-E-independent transmission of C3H mouse mammary tumor virus.
Wrona, T. and J. P. Dudley
Journal of Virology 70 (1996): 1246-1249.
ABSTRACT: C57BL/6 mice are resistant to C3H mouse mammary tumor virus (MMTV)-induced mammary tumorigenesis and lack major histocompatibility complex class II I-E molecules that are essential for presentation of C3H superantigen to T cells. T cells are needed for transmission of milk-borne MMTV from the gut to the mammary gland. In this report, we show that infectious C3H MMTV is produced by C57BL/6 mice that nurse on C3H mothers but that virus production in the mammary gland is delayed compared with that in I-E+ mouse strains.
Bramblett, D., C-L. L. Hsu, M. Lozano, K. Earnest, C. Fabritius, and J. Dudley.
Journal of Virology 69 (1995):7868-7876.
ABSTRACT: The tissue specificity of mouse mammary tumor virus (MMTV) expression is controlled by regulatory elements in the MMTV long terminal repeat (LTR). These regulatory elements include the hormone response element, located approximately between -200 and -75, as well as binding sites for NF-1, Oct-1 (OTF-1), and mammary gland enhancer factors. Naturally occurring MMTV deletion variants isolated from T-cell and kidney tumors, transgenic-mouse experiments with MMTV LTR deletions, and transient transfection assays with LTR constructs indicate that there are additional transcription regulatory elements, including a negative regulatory element (NRE), located upstream of the hormone response element. To further define this regulatory region, we have constructed a series of BAL 31 deletion mutants in the MMTV LTR for use in transient transfection assays. These assays indicated that deletion of two regions (referred to as promoter-distal and -proximal NREs) between -637 and -201 elevated basal MMTV promoter activity in the absence of glucocorticoids. The region between -637 and -264 was surveyed for the presence of nuclear protein binding sites by gel retardation assays. Only one type of protein complex (referred to as NRE-binding protein or NBP) bound exclusively to sites that mapped to the promoter-distal and -proximal NREs identified by BAL 31 mutations. The promoter-proximal binding site was mapped further by linker substitution mutations and transfection assays. Mutations that mapped to a region containing an inverted repeat beginning at -287 relative to the start of transcription elevated basal expression of a reporter gene driven by the MMTV LTR. A 59-bp DNA fragment from the distal NRE also bound the NBP complex. Gel retardation assays showed that mutations within both inverted repeats of the proximal NRE eliminated NBP binding and mutations within single repeats altered NBP binding. Intriguingly, the NBP complex was detected in extracts from T cells and lung cells but was absent from mammary gland cells. These results suggest that a factor contributing to high-level expression of MMTV in the mammary gland is the lack of negative regulation by NBP.
Mouse mammary tumor viruses with functional superantigen genes are selected during in vivo infection.
Golovkina, T. V., J. P. Dudley, A. B. Jaffe and S. R. Ross.
Proceedings of the National Academy Sciences USA
ABSTRACT: Mouse mammary tumor virus (MMTV) encodes a superantigen that is important for viral infectivity in vivo. To determine whether superantigen function was required for infection by milk-borne MMTV, we created HYB PRO/Cla transgenic mice. These mice produced a full-length, packaged viral RNA with a frameshift mutation that caused premature termination of the superantigen protein. Young HYB PRO/Cla mice showed no deletion of their cognate V beta 14+ T cells, although they shed virus in their milk. The nontransgenic offspring of the HYB PRO/Cla mice were infected with this virus, since transgene-specific viral transcripts were detected in their mammary glands. Surprisingly, these offspring demonstrated the progressive deletion of V beta 14+ T cells characteristic of exogenous MMTV (C3H) infection. Sequence analysis demonstrated that these newly acquired viruses had reconstituted superantigen open reading frames resulting from recombination between the HYB PRO/Cla and endogenous Mtv-1 proviral RNAs. Thus, there is selection during the infection process for MMTVs with functional superantigen genes.
Mouse mammary tumor virus
Dudley, J. (1994)
in R. G. Webster and A. Granoff (ed.), Encyclopedia of Virology, Saunders Scientific Publications, London, (1994) p. 853-861.
An MMTV integration site on the centromere proximal region of mouse Chromosome 11.
Rajan, L. and J. Dudley.
Mammalian Genome (1994) 5:740-743.
Golovkina, T. V., A. Chervonsky, J. P. Dudley and S. R. Ross.
Cell 69 (1992): 637-645.
ABSTRACT: Endogenous mouse mammary tumor virus (MMTV) proviruses have recently been shown to cosegregate genetically with the minor lymphocyte-stimulating loci, also termed self-superantigens. The antigenic activity has been localized to the open reading frame (ORF) protein encoded in the long terminal repeat of MMTV. We show here that unlike their nontransgenic littermates, transgenic mice expressing high levels of an ORF protein derived from the C3H exogenous MMTV specifically delete their V beta 14+ T cells and do not become infected with this virus when it is present in their mother's milk. Thus, it appears that MMTV utilizes cells of the immune system in its infection pathway, and mice that retain endogenous MMTVs should be immune to infection by exogenous virus. These results offer possible new approaches to anti-viral therapy or immunization.
Endogenous Mtv-8 or a closely linked sequence stimulates rearrangement of the downstream Vk9 gene.
Yang, J-N. and J. Dudley.
The Journal of Immunology
ABSTRACT: Mtv-8 is an endogenous retrovirus located 4.6 kb upstream of a V kappa region gene (called V kappa 9M) within the kappa-Ig locus. The proximity of these two genes resulted in several effects. Using a newly developed RNase protection assay for measuring transcription from a single endogenous provirus, we found that Mtv-8 transcription could be detected after juxtaposition of the kappa-enhancers to the normally silent provirus. Reciprocally, using the polymerase chain reaction we observed that the frequency of V kappa 9M rearrangement was 5- to 10-fold higher in spleens from Mtv-8-positive mice (BALB/c, C58.C, A/J, and B6) compared to spleens from mice that lacked the Mtv-8 provirus (C58, C.C58, NZB, and PERA/Ei). Molecular cloning and sequencing of the V kappa 9M gene from C.C58 mice (containing the kappa-locus from C58 mice on a BALB/c background) indicated that at least some Mtv-8-negative strains have a functional V kappa 9M gene. Together these data suggest that Mtv-8 or a closely linked gene enhances V kappa 9M rearrangement. Since Mtv-8 also reportedly produces a superantigen, it appears that Mtv-8 may influence both the T cell and B cell repertoires.Sequence analysis of the int-2/fgf-3 gene in aggressive human breast carcinomas.
Meyers, S. L. and J. P. Dudley
Molecular Carcinogenesis (1992) 6:243-251.
ABSTRACT: A number of primary human breast carcinomas exhibit amplification of the chromosome 11 region containing the int-2/fgf-3 proto-oncogene, and progression of breast cancer has been correlated with int-2 amplification or with certain restriction fragment length polymorphisms (RFLPs) of the int-2 gene. Using the polymerase chain reaction (PCR), we obtained the int-2 coding sequences from six primary tumors, four of which exhibited amplification of the int-2 gene and one of which exhibited amplification of the neu gene. The majority of these tumors (five of six) were aggressive, as judged by their early recurrence, metastasis, or both. Nucleotide sequencing of PCR products revealed that previously described BamHI and PstI RFLPs of the int-2 gene, as well as a new polymorphism at position 9154, were located within the intron between the second and third exons. A seventh tumor was used to localize one of the PstI RFLPs 5 bp from the splice-acceptor site of the third exon. However, none of the tumor DNAs analyzed showed differences in the int-2 protein coding regions when compared with normal placenta DNA. These results imply that aggressive human breast cancers encode an unaltered form of the int-2 protein.
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