Hiten Madhani, "Connecting split genes and junk DNA"
Oct 08, 2012 (Mon) | 4:00 PM -6:00 PM
393 Serra Mall, Herrin T-175
: Stanford, CA
Transposable elements and tandem repeats are forms of selfish DNA that are often targeted by chromatin- and RNAi-based genome defense mechanisms. The piRNA system offers an adaptive mechanism for immunity to transposons, but abundant evidence exists for innate immunity to selfish DNA. However, the nature of such mechanisms is poorly understood. The seminar will describe answers to this question obtained using a highly tractable fungal model system, Cryptococcus neoformans, which, unlike S. cerevisiae and S. pombe, uses RNAi to silencing transposons. Remarkably, a series of genetic and biochemical investigations demonstrate that the stalling of transposon pre-mRNAs in the spliceosome is a signal for RNAi. These studies identify a new function for pre-mRNA splicing and introns and connect two signature features of eukaryotic genomes: split genes and junk DNA. The disparity in the strength of gene expression signals encoded by selfish elements and genes may provide general opportunities for the evolution of genome defense. Investigations of how cells recognize selfish DNA may thereby lead to a new understanding of how eukaryotic gene expression mechanisms have evolved.
Department: Biology
Contact: Maria Magana-Lopez | 650-723-2414 | mmagana@stanford.edu
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