Background: Ph.D. in Biochemistry & Chemistry (1954) University of Wisconsin, Madison

Major Research Interests:
Cellular gene control by viral regulatory proteins.

Current Research Projects:
Dr. Green's laboratory is focusing on two research projects: (1) the molecular functions of the transcriptional repression domain encoded by the human adenovirus E1A oncogene; and (2) the regulation of human immunodeficiency virus type 1 (HIV-1) Tat transactivation of the viral promoter by cellular proteins.

Molecular functions of the adenovirus (Ad) E1A transcription repression domain.

Dr. Green's laboratory has long been involved in the study of Ad E1A oncoprotein and the remarkable growth regulatory modifications that it induces in mammalian cells. The current project of the laboratory focuses on the transcription repression domain of the E1A 243R oncoprotein that is essential for induction of cell cycle progression, cell immortalization, and neoplastic transformation. Extensive work from this laboratory by cell microinjection and by in vitro transcription repression using recombinant E1A polypeptides has mapped the E1A repression domain to sequences within the N-terminal 80 amino acids (E1A 1-80 polypeptide). In studies to identify the functional cellular target(s) of E1A repression, TBP (TFIID) was found to efficiently overcome E1A repression in vitro and to interact directly with the N-terminal sequence of E1A 1-80. In mechanistic studies, E1A 1-80 was shown to disrupt the interaction of TBP with the TATA box element. Dr. Green is now investigating in detail the molecular mechanisms by which the E1A N-terminal domain targets E1A-repressible cellular promoters involved in growth regulation and cell differentiation through interaction with promoter bound p300/CBP and disrupting specific TBP (TFIID)/TATA box complexes. As a long term and systematic global investigation, this laboratory proposes to identify (i) the natural cellular promoter targets of E1A functional domains during virus infection and in Ad-transformed cells by chromatin immunoprecipitation analysis (CHIP), and (ii) the cellular proteins modulated by E1A functional domains using recently developed proteomic methodology. These approaches are important for establishing the physiological significance of the multiple cellular gene targets reported for the E1A oncoprotein by transient expression analysis and for developing a detailed molecular understanding of the role of E1A functional domains in the regulation of cellular proliferation.

Regulation of Tat transactivation of the HIV-1 promoter by cellular protein(s).

Recent studies indicate that the HIV-1 encoded Tat transactivator protein is a realistic target for the development of a new AIDS therapy. Dr. Green's laboratory has shown that a human protein termed TAP (Tat Associated Protein) interacts strongly and specifically with the HIV-1 Tat protein. Recent studies by this laboratory have provided several direct lines of evidence that TAP is essential for HIV-1 Tat function both in vivo and in vitro. Systematic analysis of HIV LTR transcription in vitro have provided strong support for the intriguing conclusion that one TAP domain can stimulate transcription elongation of the HIV-1 genome in vitro, remarkably by over 200-fold. A second TAP domain acts as a dominant negative inhibitor of HIV-1 LTR transcription in vitro. Future long term studies are aimed towards: (i) the development of a mechanistic understanding of TAP stimulation of transcriptional elongation of the HIV-1 LTR, (ii) the development of human cell lines in which TAP can be conditionally inactivated so that the relationship between TAP function and HIV-1 Tat transactivation can be unequivocally tested, and (iii) the exploration of small TAP fusion polypeptides as possible antagonists of HIV-1 Tat function and AIDS therapy.

Representative Research Publications:

1. Boyd, J., Loewenstein, P.M., Tang, Q., Yu, L., and Green, M. (2002). The adenovirus 2 E1A N-terminal domain sequence requirements for repression of transcription in vitro and in vivo correlate with those required for E1A interference with TBP/TATA complex formation. J. Virol. 76: 1461-1474.
2. Green, M., Thorburn, A., and Loewenstein, P.M. (1998). Cell microinjection: in vivo analysis of the functional domains of viral regulatory proteins. Meth. Molec. Med. 21: 169-193.
3. Loewenstein, P.M., Song, C.Z., and Green, M. (1998). In vitro transcription: Probing the molecular functions of adenovirus regulatory protein. Meth. Molec. Med. 21: 157-168.
4. Song, C.Z., Loewenstein, P.M., Toth, K., Tang, Q., Nishikawa, A., and Green, M. (1997). The adenovirus E1A repression domain disrupts the interaction between the TATA-binding protein (TBP) and the TATA box in a manner reversible by TFIIB. Molec. Cell. Biol. 17: 2186-2193.
5. Song, C.Z., Loewenstein, P.M., Toth, K., and Green, M. (1995). Transcription factor TFIID is a direct functional target of the adenovirus E1A transcription-repression domain. Proc. Nat. Acad. Sci. USA 92: 10330-10333.
6. Song, C.Z., Tierney, C.J., Loewenstein, P.M., Pusztai, R., Symington, J.S., Tang, Q., Toth, K., Nishikawa, A., Bayley, S.T., and Green, M. (1995). Transcriptional repression by human adenovirus E1A N-terrninus/conserved domain 1 polypeptides in vivo and in vitro in the absence of protein synthesis. J. Biol. Chem. 270: 23263-23267.
7. Yu, L., Loewenstein, P.M., Zhang, Z., and Green, M. (1995). In vitro interaction of the human immunodeficiency virus type 1 Tat transactivator and the general transcription factor TFIIB with the cellular protein TAP. J. Virol. 69: 3017-3023.
8. Song, C.Z., Loewenstein, P.M., and Green, M. (1995). Repression in vitro by human adenovirus E1A protein domains, of basal and Tat-activated transcription of the human immunodeficiency virus type 1 long terminal repeat. J. Virol. 69: 2907-2911.
9. Song, C.Z., Loewenstein, P.M., and Green, M. (1994). Transcriptional activation in vitro by the human immunodeficiency virus type 1 Tat protein: Evidence for specific interaction with a coactivator(s). Proc. Nat. Acad. Sci. USA 91: 9357-9361.
10. Desai, K., Loewenstein, P.M., and Green, M. (1991). Isolation of a cellular protein that binds to the human immunodeficiency virus Tat protein and can potentiate transactivation of the viral promoter. Proc. Nat. Acad. Sci.USA 88: 8875-8879.

1. NIH/NIAID Research Career Award 5 K06 AI04739-41 entitled "Biochemistry of Viral Replication;" project period 09/01/77 - 08/31/07.
2. NIH grant 2 R01 CA29561-43 entitled "Biochemical Functions of Adenovirus Oncogenes;" project period 07/01/96 - 03/31/07.