The long term goal of this work is to understand, in precise molecular terms, how cell-type specific genes in budding yeast are transcriptionally repressed and to apply the principles developed from these studies to more complex organisms. The proposal can be divided into three basic questions: (l) How do pairs of homeodomain proteins (exemplified by alpha1 and alpha2) recognize with high affinity and specificity target DNA sequences? (2) What is the mechanism of action of a general transcriptional repression system (SSN6/TUP1) in yeast? (3) Are the components of the repression machinery and the mechanisms of repression conserved in more complex organisms? The experimental approaches emphasize the use of purified proteins and biochemical experiments to deduce molecular mechanisms. Genetic approaches in yeast are utilized (I) to test models developed from the biochemical studies and (2) to identify missing components of the repression system. Finally, complementation for function in yeast and PCR-based strategies are utilized to identify and analyze components of the repression systems in other organisms. Given the high degree of conservation of gene regulatory proteins and general transcription factors among all eucaryotes, it seems likely that many of the principles developed for the yeast proteins covered in this proposal will apply in other settings. A basic understanding of the molecular events underlying cell specialization provides not only a framework for understanding how the process can fail, but also provides the substrates and knowledge to design therapeutic strategies based on intervention.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM037049-09
Application #
2178658
Study Section
Molecular Biology Study Section (MBY)
Project Start
1986-08-01
Project End
1998-07-31
Budget Start
1994-08-01
Budget End
1995-07-31
Support Year
9
Fiscal Year
1994
Total Cost
Indirect Cost
Name
University of California San Francisco
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
073133571
City
San Francisco
State
CA
Country
United States
Zip Code
94143
Sorrells, Trevor R; Johnson, Amanda N; Howard, Conor J et al. (2018) Intrinsic cooperativity potentiates parallel cis-regulatory evolution. Elife 7:
Johnson, Alexander D (2017) The rewiring of transcription circuits in evolution. Curr Opin Genet Dev 47:121-127
Dalal, Chiraj K; Johnson, Alexander D (2017) How transcription circuits explore alternative architectures while maintaining overall circuit output. Genes Dev 31:1397-1405
Nocedal, Isabel; Mancera, Eugenio; Johnson, Alexander D (2017) Gene regulatory network plasticity predates a switch in function of a conserved transcription regulator. Elife 6:
Hanson-Smith, Victor; Johnson, Alexander (2016) PhyloBot: A Web Portal for Automated Phylogenetics, Ancestral Sequence Reconstruction, and Exploration of Mutational Trajectories. PLoS Comput Biol 12:e1004976
Sorrells, Trevor R; Johnson, Alexander D (2015) Making sense of transcription networks. Cell 161:714-23
Sorrells, Trevor R; Booth, Lauren N; Tuch, Brian B et al. (2015) Intersecting transcription networks constrain gene regulatory evolution. Nature 523:361-5
Nocedal, Isabel; Johnson, Alexander D (2015) How Transcription Networks Evolve and Produce Biological Novelty. Cold Spring Harb Symp Quant Biol 80:265-74
Howard, Conor J; Hanson-Smith, Victor; Kennedy, Kristopher J et al. (2014) Ancestral resurrection reveals evolutionary mechanisms of kinase plasticity. Elife 3:
Baker, Christopher R; Hanson-Smith, Victor; Johnson, Alexander D (2013) Following gene duplication, paralog interference constrains transcriptional circuit evolution. Science 342:104-8

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