Nilima Sarkar, Ph.D.
Senior Scientist
Cancer
Email: sarkar at bbri.org

Research Summary
At a time when it was still firmly believed that the polyadenylation of mRNA occurred only in higher organisms, we began to study mRNA polyadenylation in bacteria and established that mRNA polyadenylation also occurs in bacteria.  In the course of these studies, we identified the gene that encodes the bacterial poly(A) polymerase.  This gene, which is called pcnB, also controls the replication (plasmid copy number) of bacterial plasmids by polyadenylating a regulatory RNA molecule.  Quite recently, it was recognized that plasmids carry many of the virulence determinants of pathogenic bacteria and that some of the virulence plasmids are regulated by the pcnB gene.  This is the case in Yersinia pestis, the cause of bubonic plaque and a potential bioterrorism agent.  We are currently studying the regulation of Yersinia pestis plasmid regulation by pcnB, in the hope that this may help us understand an important aspect of its extreme virulence and provide a potential target for intervention in the pathogenic process.

Scatter plot derived from microarray analysis of Poly(A) RNA in E. coli

Selected Publications
Sarkar, N., Cao, G-j., and Jain, C. (2002) Identification of multicopy suppressors of the pcnB plasmid copy number defect in Escherichia coli. Mol. Genet. Genomics 268, 62-69.

Johnson, M.D., Popowski, J., Cao, G-j., Shen, P., and Sarkar, N. (1998) Bacteriophage T7 mRNA is polyadenylated.  Mol. Microbiol. 27, 23-30.

Sarkar, N. (1997) Polyadenylation of mRNA in prokaryotes.  Annu. Rev. Biochem. 66, 173-197.

Cao, G-j. and Sarkar, N. (1997) Stationary phase-specific mRNAs in Escherichia coli are polyadenylated.  Biochem. Biophys. Res. Commun. 239, 46-50.

Kalapos, M. P., Paulus, H., and Sarkar, N. (1997) Identification of ribosomal protein S1 as a poly(A) binding protein in Escherichia coli.  Biochimie 79,  493-502.

PubMed:
Click here for a list of publications (searches the National Library of Medicine's PubMed database.)