Functional Studies of the CDK-module of the Human Mediator Complex

University Of Colorado At Boulder, Boulder CO

Investigators

Abstract

Intellectual merit. A major challenge in modern biology is to elucidate the molecular mechanisms employed by cells to regulate expression of thousands of genes in a tissue-, signaling-, and development-specific manner. Proper regulation of gene activity is a key element of every major biological process. Specialized protein machineries can turn genes ON and OFF in a tightly regulated manner. One such protein complex, known as Mediator, is recognized as a critical regulator of gene activity from yeast to humans, yet little is known about its mechanism of action. This research project investigates a four-protein sub-complex of Mediator known as the CDK-module, which can function to either activate or repress genes. The goal of this project is to elucidate the molecular mechanism by which the CDK module activates genes including the regulatory steps at which it acts, defining the requirement for different domains of the catalytically active subunit, and delineating the roles of the other subunits. Building on the identification of specific genes in mammalian cells that are clearly regulated by the CDK-module, sophisticated biochemical and molecular biology techniques will be employed to manipulate the activity of this complex inside cells and thus obtain much needed mechanistic information. This research project will greatly improve our understanding of Mediator in particular and the evolution of gene expression control mechanisms in general. Given the quasi-universal role of Mediator in the control of gene expression, the discoveries arising from this project will have far reaching implications in the fields of cell and molecular biology. Moreover, the innovative experimental approaches not previously utilized to study Mediator in vertebrate cells will almost certainly provide novel insights. Broader impacts. The activities in this project will be carried out by a teaching-research team that strongly promotes science education and diversity in science. Preliminary results have been obtained by partnerships of undergraduate and graduate students working in a laboratory with an overall 1:1 female to male ratio and 1/3 of the lab members representing ethnic minorities. This grant will fund one such undergraduate-graduate student collaboration. Both the host institution and the Principal Investigator actively participate in programs funded by NSF and other agencies that aim to: a) increase the number of minority students earning PhDs, b) provide hands-on research experience to undergrads, c) prepare undergraduate students to pursue PhDs in the biosciences, and d) increase the representation of women in leadership positions in science and engineering. The success of these endeavors is demonstrated by the fact that every scientific publication from this research group has one or more undergraduate authors, and that several of the past undergraduate trainees are now enrolled in PhD programs. The Principal Investigator, Dr. Espinosa, is an active member of the local Hispanic community and a recognized science educator at CU-Boulder, where he is the instructor of a ~150-student undergraduate course and co-instructor in the graduate program of his home Department. He teaches topics related to his research at both venues. This grant will help to cement a culture of integrated research and education within this burgeoning group, as well as to promote diversity at the host institution.