# STRUCTURE AND FUNCTION OF THE SV40 TUMOR ANTIGEN

> **NIH NIH R01** · UNIVERSITY OF DELAWARE · 1987 · $87,642

## Abstract

The SV40 T antigen specifically interacts with the sequences at the SV40
DNA replication origin to initiate virus DNA replication and to regulate
early and late viral gene expression.  To date this interaction is
understood best at the DNA level and relatively little is known about the
polypeptide regions or domains which are involved in the binding to the
virus DNA.  Likewise, there is little information about the general
secondary structure of T antigen.  We propose to examine DNA binding
regions of T antigen by mapping polypeptide fragments that bind to the DNA
in vitro and, secondly, by studying the association of the DNA with various
previously characterized mutant T antigens.  Information on secondary
structure will be obtained by mapping internal disulfide bonds in the
polypeptide chain.  Together these experiments will provide us with data
regarding the structural organization of this protein and will allow us to
better understand the protein component of the T antigen - SV40 DNA
interaction.

T antigen is phosphorylated at multiple sites at the NH2- and COOH-terminal
regions.  We have previously determined that the protein is phosphorylated
at the NH2-terminal region in a specific stepwise process which involves
phosphorylation and dephosphorylation events.  The function of this
phosphorylation pathway is not known but the fact that it is highly
regulated suggests that it is linked to the biochemistry of the protein in
the cell.  We plan to map the specific T antigen residues which become
phosphorylated and dephosphorylated as the polypeptide matures in the
cell.  In addition, we propose to determine if there is a relationship
between these phosphorylation states and DNA or ATP binding activity.

Finally, because the subpopulation of T antigen which is present at the
cell surface is important to the mechanism of tumor rejection and may also
be involved in transformation, we propose to study the structure of this
fraction of T antigen with respect to oligomerization and phosphorylation
states.

## Key facts

- **NIH application ID:** 3173624
- **Project number:** 5R01CA036118-03
- **Recipient organization:** UNIVERSITY OF DELAWARE
- **SAM.gov UEI:** T72NHKM259N3
- **Principal Investigator:** Daniel T. Simmons
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1987
- **Award amount:** $87,642
- **Award type:** 5
- **Project period:** 1985-09-01 → 1988-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3173624

## Citation

> US National Institutes of Health, RePORTER application 3173624, STRUCTURE AND FUNCTION OF THE SV40 TUMOR ANTIGEN (5R01CA036118-03). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3173624. Licensed CC0.

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