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DOI码:10.1128/MCB.25.10.3914-3922.2005
发表刊物:Mol Cell Biol
摘要:In Tetrahymena thermophila, highly phosphorylated histone H1 of growing cells becomes partially dephosphorylated when cells are starved in preparation for conjugation. To determine the effects of H1 phosphorylation on gene expression, PCR-based subtractive hybridization was used to clone cDNAs that were differentially expressed during starvation in two otherwise-isogenic strains differing only in their H1s. H1 in A5 mutant cells lacked phosphorylation, and H1 in E5 cells mimicked constitutive H1 phosphorylation. Sequences enriched in A5 cells included genes encoding proteases. Sequences enriched in E5 cells included genes encoding cdc2 kinase and a Ser/Thr kinase. These results indicate that H1 phosphorylation plays an important role in regulating the pattern of gene expression during the starvation response and that its role in transcription regulation can be either positive or negative. Treatment of starved cells with a phosphatase inhibitor caused CDC2 gene overexpression. Expression of the E5 version of H1 in starved cells containing endogenous, wild-type H1 caused the wild-type H1 to remain highly phosphorylated. These results argue that Cdc2p is the kinase that phosphorylates Tetrahymena H1, establish a positive feedback mechanism between H1 phosphorylation and CDC2 expression, and indicate that CDC2 gene expression is regulated by an H1 phosphatase.
卷号:25
期号:10
页面范围:3914-22
是否译文:否
上一条:Unphosphorylated H1 is enriched in a specific region of the promoter when CDC2 is down-regulated during starvation.
下一条:A robust inducible-repressible promoter greatly facilitates gene knockouts, conditional expression, and overexpression of homologous and heterologous genes in Tetrahymena thermophila.