Protein Complex Marks Histones for Gene Transcription

A new study suggests that the Paf1 protein complex, which is associated with the elongating RNA polymerase II, is required for the process through which histones are "marked” by methylation during gene transcription. The study was published in the March 2003 issue of Molecular Cell.

Investigators from St. Louis University (MO, USA) studying the mechanisms that cells use to regulate the transcription of genetic information from DNA to RNA found that Paf1 was required for methylation of lysines four and 79 of histone H3 and for silencing of expression of a telomere-associated gene.

In addition, they showed that Paf1 was required for recruitment of the COMPASS methyltransferase to RNA polymerase II and that the subunits of these complexes interacted physically and genetically. Collectively, the results suggested that the Paf1 complex was required for histone H3 methylation, therefore linking transcriptional elongation to chromatin methylation.

"It turns out that some of these markers serve as a kind of roadmap for transcription, identifying which genes have and have not been expressed,” explained senior author Dr. Ali Shilatifard, a researcher in the biochemistry department of St. Louis University. "This opens the door for further study of the role these markers play in gene transcription. Once we fully understand how they function in normal cellular development, we can begin to study their role in the development of human diseases.”



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