Gene looping facilitates TFIIH kinase-mediated termination of transcription.
TFIIH is a general transcription factor with kinase and helicase activities. The kinase activity resides in the Kin28 subunit of TFIIH. The role of Kin28 kinase in the early steps of transcription is well established. Here we report a novel role of Kin28 in the termination of transcription. We show that RNAPII reads through a termination signal upon kinase inhibition. Furthermore, the recruitment of termination factors towards the 3' end of a gene was compromised in the kinase mutant, thus confirming the termination defect. A concomitant decrease in crosslinking of termination factors near the 5' end of genes was also observed in the kinase-defective mutant. Simultaneous presence of termination factors towards both the ends of a gene is indicative of gene looping; while the loss of termination factor occupancy from the distal ends suggest the abolition of a looped gene conformation. Accordingly, CCC analysis revealed that the looped architecture of genes was severely compromised in the Kin28 kinase mutant. In a looping defective sua7-1 mutant, even the enzymatically active Kin28 kinase could not rescue the termination defect. These results strongly suggest a crucial role of Kin28 kinase-dependent gene looping in the termination of transcription in budding yeast.
Department of Biological Sciences, Wayne State University, 5047 Gullen Mall Detroit, MI 48202.
Scott
S
Medler
Department of Biological Sciences, Wayne State University, 5047 Gullen Mall Detroit, MI 48202.
Athar
A
Ansari
D018844:Cyclin-Dependent Kinases / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D046912:Multiprotein Complexes / Q000378:metabolism; D009690:Nucleic Acid Conformation; D010766:Phosphorylation; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D011494:Protein Kinases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D013728:Terminator Regions, Genetic; D061806:Transcription Termination, Genetic
D046912:Multiprotein Complexes; D029701:Saccharomyces cerevisiae Proteins; D011494:Protein Kinases; C060137:carboxy-terminal domain kinase; D018844:Cyclin-Dependent Kinases; C084210:Kin28 protein kinase, S cerevisiae