Laimonis A Laimins, PhD

Guy and Anne Youmans Professor of Microbiology-Immunology
Feinberg School of Medicine

Research Interests:
The current focus of Dr. Laimins’ laboratory, is the genetic analysis of the human papillomavirus life cycle. In order to investigate the mechanisms which regulate the productive life cycle of human papillomaviruses (HPV) systems, the y have developed methods for a genetic analysis of viral functions in tissue culture systems. Papillomaviruses are small DNA viruses that induce a variety of proliferative lesions in most mammals including humans. Of the 100 types of human papillomaviruses that have been identified, a subset are associated at a high frequency with anogenital cancers and these are referred to as the high risk types Viral infection occurs into stratified epithelial cells and results in an altered pattern of differentiation from that seen in normal cells. The production of viral particles, genome amplification, capsid protein synthesis, and virion assembly is dependent upon differentiation and is restricted to suprabasal cells.. Dr. Laimins’ lab has developed methods to synthesize HPV 31 virions from cloned transfected DNA templates following differentiation in organotypic cultures as well as suspension in semi-solid media. These methods allowed them to begin a genetic analysis of HPV functions during the productive life cycle with a major focus on the activities of E1 and E2. They have identified the roles for cis sequences in modulating plasmid maintenance and characterized the mechanisms by which a switch occurs from maintenance to amplification replication. Additional studies have identified an E2 repressor, and examined the low-risk HPV life cycle. Recent studies from the laboratory of Dr. Laimins, identified important roles for E6 in plasmid maintenance and E5 for differentiation-dependent activation of late viral functions. These are novel functions for proteins whose role in the viral life cycle was previously unknown.