Sohail Malik, Ph.D.Research Associate Professor
Laboratory of Biochemistry and Molecular Biology
Dr. Malik studies the regulation of gene expression in eukaryotic cells. Building on the work of Rockefeller's Robert G. Roeder, research by Dr. Malik and others has contributed to the concept that transcription of messenger RNA genes by RNA polymerase II (Pol II) is a multistep process controlled by the orchestrated action of numerous accessory factors. Of these, the so-called general transcription factors (GTFs) typically suffice for accurate, low-level transcription of naked DNA templates in vitro. Tissue- and gene-specific targeting of these factors to promoter regions of a given gene is achieved via transcriptional activators, which are responsive to various cellular signals and bind to specific DNA sequences that control expression of the gene. Efficient functional coupling of activators and the general transcription machinery is in turn dependent upon certain coactivators, foremost among them being the multisubunit Mediator complex. Working in Dr. Roeder’s group, Dr. Malik was among the first to isolate the Mediator. He and his colleagues then went on to characterize it extensively, both structurally and functionally.
In recent work, Dr. Malik and his colleagues have used nuclear receptors, specifically HNF-4, to probe transcriptional mechanisms. HNF-4, an important regulator of both fetal development and organogenesis and adult physiology, is primarily expressed in the liver and intestine in adult animals. Overall, evidence from Dr. Malik's group, as well as from many other laboratories, increasingly highlights the central role of Mediator in unifying the expression programs of individual genes. It is likely that Mediator functions as an "integrative hub" that assimilates the multiple signals feeding into the gene and modulates the appropriate transcriptional response.
After graduating from Yale University, Dr. Malik received a Ph.D. in microbiology from Columbia University in 1987. He was a postdoctoral fellow in Robert G. Roeder's Rockefeller University laboratory from 1988 to 1992. He was senior scientist in the department of cardiovascular molecular biology at Lederle Laboratories from 1993 to 1995. He returned to Dr. Roeder's lab in 1996 as a research associate and was promoted to research assistant professor in 2000 and research associate professor in 2008.