Robert Landick

Research Description:
We study regulatory mechanisms that control gene expression through changes in RNA chain elongation in organisms ranging from bacteria and humans. E. coli offers an ideal model system in which to ask detailed questions about RNA chain elongation and its control. We are tackling the problem by first analyzing the interaction of RNA polymerase with RNA and DNA sequences and structures that direct pausing, arrest, and termination during chain elongation. We parallel these biochemical studies with genetic analysis of RNA polymerase. Using methods for regulated overproduction of the b and b’ subunits of RNA polymerase, we have isolated and studied amino acid substitutions that alter transcriptional termination or that compromise cell growth. We are now analyzing subunit interactions by isolating suppressors of some of these substitutions. We also collaborate to use biophysical methods of optical microscopy for single-molecule analysis of transcription and 2D electron crystallography to study the activity and structure of transcription complexes. Finally, we have undertaken a study of RNA chain elongation by human RNA polymerase II that is beginning to reveal the nature of signals that control its transcript elongation.

Representative Publications:

Palangat, M., T. I. Meier, R. G. Keene and R. Landick. 1998. Transcriptional pausing at +62 of the HIV-1 nascent RNA modulates formation of the TAR RNA structure. Mol. Cell 1:1033-1042.

Wang, D., K. Severinov, and R. Landick. 1997. Preferential interaction of the his pause RNA hairpin with RNA polymerase β subunit residues 904-950 correlates with strong transcriptional pausing, Proc. Natl. Acad. Sci. USA 94:8433-8438.

Heisler, L. M., G. Feng, D. J. Jin, C. A. Gross, and R. Landick. 1996. Amino acid substitutions in the two largest subunits of Escherihcia coli RNA polymerase that suppress a Defective Rho termination factor affect different parts of the transcription complex.