Zhi-Ren Liu, Assistant Professor BS: Hunan Teacher's University, P. R. China MS: University of Xiangtan, P. R. China PhD: The Florida State University Discipline: Biochemistry & molecular biology (334) 844-1536, Fax: 334-844-1519 zrliu@acesag.auburn.edu URL: http://www.ag.auburn.edu/~zrliu

Courses Taught:

• BCHE 7200 - Advanced Biochemistry I
• BCHE 7210 - Advanced Biochemistry II

Research Program:

My group's research interests are in RNA helicases, a family of proteins that function in the cells through local unwinding of complex RNA structures. Members of this family are found in almost all organisms, from bacteria to human. RNA helicases are involved in every process of RNA metabolism in cells. Our interests in RNA helicase are two folds; (1) we are interested in understanding the mechanism with which the RNA helicasese, as bio-motor, perform the RNA unwinding activity. The central question in this aspect is how the RNA helicases transform the energy of NTP hydrolysis and/or binding into mechanical (conformational) work on RNA, and (2) we are interested in elucidating the mechanism with which the functions of RNA helicasese is controlled. How does the RNA helicase exert their activity precisely in time and space is our ultimate question.

Currently, the p68 RNA helicase is studied in the laboratory as an example. The protein is expressed in all dividing cells of different vertebrates, but not in quiescent cells. The protein shows clear cell cycle-related localization in nuclear. P68 is highly conserved throughout evolution. Using our unique dsRNA-protein crosslinking technique, we have detected that p68 RNA helicase interacts with a transient RNA duplex, the U1:5'ss duplex, during the pre-mRNA splicing process. Our laboratory is involved in extensive characterization of the protein using a combination of biochemical, molecular biological, genetic, and cell biological approaches. By these studies, we hope to understand (1) the functions of p68 in the pre-mRNA splicing process, (2) the mechanism with which p68 unwinds the duplex RNA.

Positive-strand RNA viruses belong to a large family of viruses that cause widespread disease. The virus genome contains a single-stranded RNA with positive polarity. To maintain proper viral replications, the nascent transcripts must be unwound from its complementary template RNA soon after transcription. On the other hand, the template RNA for transcription is highly structured, specially at it's 5' and 3' termini. To synthesize a new strand of RNA, the virus replication machinery must also unwind such structures. We are interested to investigate the functions of RNA helicasese in the replication of RNA virus. Currently, we are involved in developing an assay system to analyze the helicase activity in an in vitro virus replication process.