Michael E. Dresser, M.D., Ph.D.

B.A., Duke University, 1975
M.D., Duke University Medical Center, 1985
Ph.D., Duke University, 1985
 
Joined OMRF Scientific Staff in 1989.
 
e-mail: Mike-Dresser@omrf.ouhsc.edu

Delivery of the proper number of chromosomes from one generation to the next requires specialized chromosome structures and activities during meiosis. Chromosomes of a pair must align side-by-side, exchange parts, and then move apart in the first meiotic division. These processes depend on an intricate series of carefully coordinated, well-conserved events which we want to understand in molecular detail. Problems in carrying out these events contribute to infertility, to birth defects and to cancer. We hope that understanding the molecular mechanisms involved will allow detection of people at risk and correction of defects before they cause unhealty outcomes.

Yeast meiotic chromosomes stained with DAPI to label DNA (blue) and with antibody to detect Ndj1 protein (red).

Our research employs the yeast Saccharomyces cerevisiae as a model organism and proceeds in two complementary projects. The first project addresses the question of how chromosomes pair (align side-by-side), a process which depends on the NDJ1 gene discovered in our laboratory.
 
This gene encodes a protein that localizes to the telomeres (the ends) of the chromosomes and somehow causes, or allows, them to cluster at a single site against the inside of the nuclear membrane preparatory to pairing. Failure to form this cluster is associated with defects in a number of downstream processes and results in missegregation of chromosomes and aneuploidy. Current research in this area is aimed at identifying interacting genes, at determining how the clustering occurs and at discovering how the cluster works to foster chromosome pairing. The second project addresses the question of how chromosomes exchange parts and repair the damage that occurs in the process. This project was initiated when we (and others) discovered the DMC1 gene which encodes a well-conserved member of a family of proteins known best for their roles in processing damaged DNA. We have identified genes that interact with DMC1 and are exploring their roles in DNA repair and recombination.

Dernburg, A.F., McDonald, K., Moulder, G., Barstead, R., Dresser, M., Villeneuve, A.M. (1998) Meiotic recombination in C. elegans initiates by a conserved mechanism, and is dispensable for homologous chromosome synapsis. Cell 94: 387-398.
 
Conrad, M.N., Dominguez, A.M., Dresser, M.E., (1997) Ndj1p, a meiosis-specific telomere protein required for normal chromosome synapsis and segregation in yeast. cience 276: 1252-1255.
 
Dresser, M.E., Ewing, D., Conrad, M., Dominguez, A., Barstead, R., Jiang, H., Kodadek, T. (1997) DMC1 functions in a Saccharomyces cerevisiae meiotic pathway that is largely independent of the RAD51 pathway. Genetics 147: 533-544.

Sigma Xi
Genetics Society of America
American Association for the Advancement of Science
American Society for Microbiology