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Rathi, Abhilasha Vikas (2008) ROLE OF MULTIPLE DOMAINS OF T ANTIGEN IN GENE REGULATION AND TRANSFORMATION. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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SV40 large T antigen (TAg) is a dominant acting oncoprotein that elicits transformation of many cell types and induces tumors in rodents. TAg induces transformation, in part, by disabling the functions of tumor suppressors such as pRb and p53. This dissertation is aimed to determine if inactivation of Rb and p53 are the major TAg activities required for transformation or if additional activities contribute.To determine whether Rb-family protein inactivation by the J domain of TAg is required for induction of intestinal hyperplasia, we have generated transgenic mice that express a J domain mutant (D44N) in villus enterocytes. In contrast to wild-type T antigen, the D44N mutant is unable to induce enterocyte proliferation. Unlike mice expressing wild-type TAg, mice expressing D44N do not reduce the protein levels of p130 and are also unable to dissociate p130-E2F DNA binding complexes. To determine if Rb inactivation is sufficient for the induction of hyperplasia or if progression to dysplasia requires some activity in the C-terminus of TAg (independent of p53), I have screened several transgenic lines expressing an amino-terminal mutant of TAg (N136) in villus enterocytes. I found that these mice develop intestinal hyperplasia, although not as early as wild-type TAg does, suggesting that the inactivation of Rb family members is sufficient to induce this phenotype. Furthermore, the appearance of signs of dysplasia was significantly delayed. I performed global analysis of gene regulation in MEFs and in mouse intestinal epithelium expressing TAg or various mutants. In mouse intestine most of the gene regulation is dependent on binding and inactivation of Rb-proteins by the LXCXE motif and J domain. Regulated genes are involved in cell cycle and proliferation. In MEFs genes belonging to cell cycle, apoptosis and growth factors are differentially regulated by TAg and its mutants. Additionally, we found upregulation of immune response genes by TAg requires the LXCXE motif and some activity mapping to the C-terminus of TAg for their regulation. Significant numbers of genes were found to be regulated independently of the LXCXE motif, J domain and p53 binding domain. This suggests activity independent of these functions.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Rathi, Abhilasha Vikasabr1@pitt.eduABR1
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairPipas, James M.pipas@pitt.eduPIPAS
Committee MemberStronach, Bethstronach@pitt.eduSTRONACH
Committee MemberLiu,
Committee MemberBrodsky, Jeffery L.jbrodsky@pitt.eduJBRODSKY
Committee MemberGrabowski, Paula A.pag4@pitt.eduPAG4
Date: 16 June 2008
Date Type: Completion
Defense Date: 20 February 2008
Approval Date: 16 June 2008
Submission Date: 20 February 2008
Access Restriction: 5 year -- Restrict access to University of Pittsburgh for a period of 5 years.
Institution: University of Pittsburgh
Schools and Programs: Dietrich School of Arts and Sciences > Biological Sciences
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: SV40; TRANSFORMATION
Other ID:, etd-02202008-105301
Date Deposited: 10 Nov 2011 19:31
Last Modified: 15 Nov 2016 13:36


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