On Oct. 2, the department of Mycology will host Prof. Alexander Johnson, Microbiology and Immunology, UCSF, for a seminar entitled “How Evolving Transcription Circuits Produced a Fungal Pathogen of Humans”.
The seminar will be held at 4pm, Room Jean-Paul Aubert, Bâtiment Fernbach.
Here is an abstract for this seminar:
“Transcription circuits in cells are often viewed as optimized solutions, sculpted by the power of natural selection. But can this view account for the basic logic of transcription circuits? Why, for example, are some genes controlled positively, others negatively and some by both mechanisms? Why is cooperative binding of regulatory proteins to DNA so common? Why do many circuits seem bewilderingly complex? To rationalize the structure of modern circuits, we have been examining the evolutionary processes that produce them. We have reconstructed the evolutionary history of several transcriptional circuits across a large portion of the fungal lineage (the ascomycetes which include Saccharomyces cerevisiae and Candida albicans) nominally representing 300 million years of diversification. Although the DNA-binding specificity of transcription regulators are often preserved over these evolutionary times, the connections between regulators and the genes they control change rapidly. The ease of these wiring changes results from several basic features of transcription regulation, including regulatory protein modularity, cooperative binding, and the low information content of cis-regulatory sequences. Some wiring changes provide novel phenotypes, while others seem to preserve ancestral circuit output but alter the structure of the circuit through which that output is achieved. We found that, over evolutionary time scales, circuits can move through different wiring solutions without disrupting the output and that this process can lead to profound circuit diversification across species. We conclude that many aspects of modern transcription circuits are more easily explained through a knowledge of the evolutionary pathways of least resistance than through “first-principle” logic.”
For more information about this seminar, contact Christophe d’Enfert (firstname.lastname@example.org)