Stanford University
School of Medicine Department of Pathology
300 Pasteur Drive
SUMC Edwards R270
Stanford, CA 94305
(650) 725-4907 (Teresa
Wang)
(650) 725-4908
(Laboratory)
(650) 725-6902 (Fax)
Research interest:
The
long-term goal of our lab research is to understand the molecular mechanisms
involved in maintaining genome stability. To this end, we investigate what and
how trans-acting factors are involved in maintaining genome stability. The major
focuses of our ongoing research activities are:
(I) To investigate mutator phenotypes induced by aberrant
chromosome replication.
Cancer
is a genetic disease, arising from an accumulation of mutations that promote
clonal selection of cells with increasing mutations i.e. mutator phenotype. The
accumulation in cancer cells genome of hundreds of thousands of mutations such
as insertion and deletions of sequences and alterations of repeat sequences is
the diagnostic feature of cancer. We investigate what and how mutations in
enzymes/proteins essential for chromosome replication can cause an aberrant
replication resulting in genomic instability.
We
have used Schizosaccharomyces pombe (S. pombe) and Saccharomyces
cerevisiae (S. cerevisiae) as the model organisms to identify
replication mutants that have an elevated mutation frequency in deletion
or duplication of genomic sequences flanked by short direct repeats as
well as alterations of dinucleotide repeats. Identical or similar mutations are
being introduced into mammalian homolog replication enzymes/proteins to
investigate whether they could generate a mutator phenotype in animal cell
lines. We plan in the near future to express these replication mutants with a
tissue specific promoter in a specific organ of mice to test their carcinogenic
effect during the tissue development.
(II) To investigate the genetic and biochemical elements that
maintain the DNA replication checkpoint.
There
is a category of genes encoding components of the cell cycle checkpoints. Cell
cycle checkpoints are positions of control to ensure the order of events in the
cell cycle and to integrate DNA repair with cell cycle progression.
Our
laboratory has used fission yeast as the model organism to investigate what is
required for cells to activate intra-S phase checkpoint and how cells prevent
premature mitotic entry when DNA replication is unfinished or improperly
initiated. We have used various mutants of chromosome replication genes to
investigate what cell cycle checkpoint gene products are activated and how they
monitor S phase delay and S phase arrest. We first use genetic approaches to
identify genes that sense and transduce the signals of replication delay or block.
We then use biochemical methods to investigate these S-phase checkpoint gene
products. Our future goal is to introduce mutations of the S phase checkpoint
genes into mammalian homolog genes to directly test the carcinogenic effect in
mammalian cells.
Recent Publications:
1.
Griffiths, D. J. F., Uchiyama, M., Nurse, P.,
and Wang, T. S.-F. A novel mutant allele of the chromatin bound fission yeast
checkpoint protein Rad17 separates the DNA structure checkpoint. Submitted.
1999.
2.
Kelman, Z., Zou, S., Arroyo, M., Wang, T. S.-F.,
and Hurwitz, J. The C-terminal region of Schizosaccharomyces pombe PCNA
is essential for DNA polymerase activity. Proc. Natl. Acad. Sci. U.S.A.96:
9515-9520. 1999.
3.
Conger, K. L., Liu, J.-S., Kuo, S.-R., Chow,
L. T., and Wang, T. S.-F. Human papillomavirus DNA replication: Interactions
between the viral E1 and two subunits of human DNA polymerase a
/primase. J. Biol. Chem. 274: 2696-2705. 1999
4.
Liu, V. F., Bhaumik, D., and Wang, T. S.-F.
Mutator phenotype induced by aberrant replication. Mol. Cell. Biol. 19:1126-1135.
1999.
5.
Arroyo, M. P. and Wang, T. S.-F. Schizosaccharomyces
pombe replication proteins. In Genetic Approaches to Eukaryotic Replication
and Repair. Methods. A Companion to Methods in Enzymology. Academic Press. 18:
335-348. 1999.
6.
Wang, T. S.-F., Conger, K. L., Copeland, W.
C., and Arroyo, M. P., Eukaryotic DNA polymerases. In Eukaryotic DNA
replication: a practical approach (ed. S. Cotterill), Oxford University Press.
Chapter 3, 67-92. 1999.
7.
Bhaumik, D. and Wang, T. S.-F. Mutational effect
of fission yeast Pola on cell cycle
events. Mol. Biol. Cell. 9: 2107-2123. 1998.
8.
Arroyo, M. P. and Wang, T. S.-F. Mutant PCNA
alleles are associated with cdc phenotypes and sensitivity to DNA-damage
in fission yeast. Mol. Gen. Genetics 257: 505-518. 1998.
9.
Zou, S., Gibbs, E., Kelman, Z., MacNeill, S.
A., Wang, T. S.-F., O'Donnell, M., and Hurwitz, J. DNA polymerase d
isolated from S. pombe contains five subunits. Proc. Natl. Acad. Sci.
USA. 94: 11244-11249. 1997.
10.
Galli, I., Uchiyama, M., and Wang, T.
S.-F. DNA replication and order of cell cycle events: A role for protein
isoprenylation? Biol. Chem. 378: 963-973. 1997
11.
Uchiyama, M., Galli, I., Griffiths, D. J. F.,
and Wang, T. S.-F. A novel mutant allele of Schizosaccharomyces pombe rad26
defective in monitoring the S phase progression to prevent premature mitosis.
Mol. Cell. Biol. 17: 3103-3115. 1997.
12.
Arroyo, M. P., Tan, C. K., Downey, K. M., So,
A. G., and Wang, T. S.-F. Schizosaccharomyces pombe proliferating cell
nuclear antigen mutations affect DNA polymerase d
processivity J. Biol. Chem. 271: 15971-15980. 1996.
13. Wang, T. S.-F.
Cellular DNA Polymerases. In: DNA Replication in Eukaryotic Cells: Concepts,
Enzymes, & Systems. Edited by M. L. DePamphilis. A Monograph of Molecular
Biology by Cold Spring Harbor Laboratory Press. Chapter 15, pp461-493. 1996.