Joan Steitz is interested in the multiple roles played by noncoding RNA–protein complexes in gene expression in vertebrate cells.
Mystery of Noncoding RNAs in Mammalian Cells
MicroRNAs (miRNAs) are a new exciting class of noncoding RNAs. These tiny (22 nucleotides long) RNAs regulate translation by interacting with messenger RNAs. We have discovered that miRNAs sometimes stimulate and sometimes repress translation, depending on the cell cycle. We are studying their biogenesis, which is disrupted in many disease states, and how they function.
Another set of RNAs under study in the lab are made when viruses infect cells to either replicate or transform, causing tumors. We are studying noncoding RNAs (including miRNAs) from Epstein-Barr virus, which causes infectious mononucleosis as well as several tumors. Likewise, Kaposi's sarcoma virus makes a mysterious large nuclear RNA, whose function we are trying to pin down. Herpesvirus saimiri, a monkey virus, makes noncoding RNAs that bind host miRNAs to manipulate their function.
Projects are available studying the different noncoding RNAs listed above.