Kristen Johansen
Iowa State University, IA·Genetics
Cells must control not just which genes are on, but how strongly and when. Housekeeping genes that handle routine maintenance run steadily, while genes for development, stress responses and immunity need careful dialing up and down.
- Fields
Genetics
Biochemistry
Biology
- Topics
chromatin
histone modification
epigenetics
- Grants
- 1 known grant, through Apr 2027
What they work on
- Test whether the histone marks H3K9me2, H3S10ph and H4K16ac jointly fine-tune gene expression by setting how permissive chromatin is for transcription, using non-dividing salivary gland cells from third-instar Drosophila larvae.
- Target the histone writers JIL-1 (H3S10 kinase), Su(var)3-9 (H3K9 methyltransferase) and MOF (H4K16 acetyltransferase) to defined chromatin sites with lacI or GAL4 fusion constructs, individually or sequentially, and measure induced changes in marks and chromatin structure.
- Determine which chromatin remodeling factors are recruited or lost at targeted sites, and how nucleosome array organization and reporter gene expression change in response.
- Test whether the three writers cross-regulate each other by mutating known JIL-1 phosphorylation sites on Su(var)3-9 and candidate MOF acetylation sites on JIL-1.
More about the research
Much of this control happens through chemical marks placed on histones, the proteins that package DNA into chromatin, by enzymes called histone writers. How several writers coordinate to produce fine, dial-like control rather than a simple on-off switch is poorly understood.
Why it matters
Fine control of gene expression levels underlies development, stress responses and immune function, and the histone-modifying enzymes studied here have counterparts across animals. Clarifying how these writers cooperate and regulate one another adds to basic understanding of how chromatin accessibility sets transcription levels, which could eventually inform how misregulated histone modification contributes to disease.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Robert J Duronio
University of North Carolina at Chapel Hill, NC·Genetics
Determine what is required for the coordinated production of replication-dependent histone mRNAs, using biochemical and genetic approaches in Drosophila to test the role of the Histone Locus Body, the nuclear structure that assembles at clustered histone genes.
Michael Joseph Buck
University at Buffalo, NY·Genetics
Determine how transcription factors recognize binding sites wrapped on a nucleosome, the DNA spool unit, using the in vitro Pioneer-seq assay to compare sites at every nucleosome position and across sequence variants.
Motoki Takaku
University of North Dakota, ND·Genetics
Identify the nucleosome positions and shapes that let the pioneer factor GATA3 open chromatin and drive the mesenchymal-to-epithelial transition in triple-negative breast cancer cells, using high-resolution nucleosome mapping.
The school
Iowa State University: 23 labs on PI Pages, $462M a year on research, 327 research doctorates a year.
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