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Full-Text Articles in Molecular Biology

Dna-Guided Establishment Of Canonical Nucleosome Patterns In A Eukaryotic Genome, Leslie Y. Beh, Noam Kaplan, Manuel M. Muller, Tom W. Muir, Laura F. Landweber Dec 2014

Dna-Guided Establishment Of Canonical Nucleosome Patterns In A Eukaryotic Genome, Leslie Y. Beh, Noam Kaplan, Manuel M. Muller, Tom W. Muir, Laura F. Landweber

University of Massachusetts Medical School Faculty Publications

A conserved hallmark of eukaryotic chromatin architecture is the distinctive array of well-positioned nucleosomes downstream of transcription start sites (TSS). Recent studies indicate that trans-acting factors establish this stereotypical array. Here, we present the first genome-wide in vitro and in vivo nucleosome maps for the ciliate Tetrahymena thermophila. In contrast with previous studies in yeast, we find that the stereotypical nucleosome array is preserved in the in vitro reconstituted map, which is governed only by the DNA sequence preferences of nucleosomes. Remarkably, this average in vitro pattern arises from the presence of subsets of nucleosomes, rather than the whole array ...


A Systematic Survey Of An Intragenic Epistatic Landscape, Claudia Bank, Ryan T. Hietpas, Jeffrey D. Jensen, Daniel N. Bolon Oct 2014

A Systematic Survey Of An Intragenic Epistatic Landscape, Claudia Bank, Ryan T. Hietpas, Jeffrey D. Jensen, Daniel N. Bolon

University of Massachusetts Medical School Faculty Publications

Mutations are the source of evolutionary variation. The interactions of multiple mutations can have important effects on fitness and evolutionary trajectories. We have recently described the distribution of fitness effects of all single mutations for a nine amino acid region of yeast Hsp90 (Hsp82) implicated in substrate binding. Here, we report and discuss the distribution of intragenic epistatic effects within this region in seven Hsp90 point mutant backgrounds of neutral to slightly deleterious effect, resulting in an analysis of more than 1000 double-mutants. We find negative epistasis between substitutions to be common, and positive epistasis to be rare – resulting in ...


A Conserved Flagella-Associated Protein In Chlamydomonas, Fap234, Is Essential For Axonemal Localization Of Tubulin Polyglutamylase Ttll9, Tomohiro Kubo, Haru-Aki Yanagisawa, Zhongmei Liu, Rie Shibuya, Masafumi Hirono, Ritsu Kamiya Jan 2014

A Conserved Flagella-Associated Protein In Chlamydomonas, Fap234, Is Essential For Axonemal Localization Of Tubulin Polyglutamylase Ttll9, Tomohiro Kubo, Haru-Aki Yanagisawa, Zhongmei Liu, Rie Shibuya, Masafumi Hirono, Ritsu Kamiya

University of Massachusetts Medical School Faculty Publications

Tubulin undergoes various posttranslational modifications, including polyglutamylation, which is catalyzed by enzymes belonging to the tubulin tyrosine ligase-like protein (TTLL) family. A previously isolated Chlamydomonas reinhardtii mutant, tpg1, carries a mutation in a gene encoding a homologue of mammalian TTLL9 and displays lowered motility because of decreased polyglutamylation of axonemal tubulin. Here we identify a novel tpg1-like mutant, tpg2, which carries a mutation in the gene encoding FAP234, a flagella-associated protein of unknown function. Immunoprecipitation and sucrose density gradient centrifugation experiments show that FAP234 and TTLL9 form a complex. The mutant tpg1 retains FAP234 in the cell body and flagellar ...