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Dilip Nag, Ph.D.
Dilip Nag, Ph.D.
- Arbovirus Laboratory
- Adjunct Assistant Professor, School of Public Health, Biomedical Sciences
- Ph.D., University of Calcutta, India
- Postdoctoral training: Washington University, St. Louis
- Postdoctoral training: University of Chicago
- Postdoctoral training: University of North Carolina
Research in our laboratory concerns the mechanism of meiotic development using the yeast Saccharomyces cerevisiae as a model eukaryote. Meiosis is a special kind of cell division process in which the chromosome number is reduced to half in the product germ cells. A defect in the process can lead to severe birth defects and several other heritable genetic disorders. S. cerevisiae provides an excellent model system because of its powerful genetics and the sequence of the whole genome is available. To gain new insights into meiotic development, we have been studying a number of genes that are expressed exclusively during meiosis.
A second project concerns the stability of inverted DNA repeats in the genome. The sequence arrangement of inverted repeats allows the sequence to exist in one of two alternative structures: the normal interstrand base-paired duplex DNA or an intrastrand base-paired cruciform structure, which is a substrate for several cellular nucleases. Inverted repeated sequences are found naturally in both prokaryotic and eukaryotic genomes. Present in functionally important regions such as operator sequences, replication origins, transcription-termination sites, they play important roles with respect to the function of these genomic regions. It is important that such sequences be maintained in the genome. Our results indicate that short palindromic sequences are highly stable in vivo and mechanisms have been developed to maintain such sequences even when they are fortuitously extruded into cruciform conformation. Long palindromic sequences, on the contrary, make the genome unstable and such sequences are removed from the genome by recombinational repair. Currently, we are investigating the mechanism of genomic instability caused by the presence of long palindromic sequences in the genome.