Hsl7p, the yeast homologue of human JBP1, is a protein methyltransferase
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
Authors: Lee, JH; Cook, JR; Pollack, BP; Kinzy, TG; Norris, D; Pestka, S
The yeast protein Hsl7p is a homologue of Janus kinase binding protein 1, JBP1, a newly characterized protein methyltransferase. In this report, Hsl7p also is shown to be a methyltransferase. It can be crosslinked to [H-3]S-adenosylmethionine and exhibits in vitro protein methylation activity. Calf histones H2A and H4 and bovine myelin basic protein were methylated by Hsl7p, whereas histones H1, H2B, and H3 and bovine cytochrome c were not. We demonstrated that JBP1 can complement Saccharomyces cerevisiae with a disrupted HSL7 gene as judged by a reduction of the elongated bud phenotype, and a point mutation in the JBP1 S-adenosylmethionine consensus binding sequence eliminated all complementation by JBP1. Therefore, we conclude the yeast protein Hsl7p is a sequence and functional homologue of JBP1. These data provide evidence for an intricate link between protein methylation and macroscopic changes in yeast morphology. (C) 2000 Academic Press.
Regulation of chromosome stability by the histone H2A variant Htz1, the Swr1 chromatin remodeling complex, and the histone acetyltransferase NuA4
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Authors: Krogan, NJ; Baetz, K; Keogh, MC; Datta, N; Sawa, C; Kwok, TCY; Thompson, NJ; Davey, MG; Pootoolal, J; Hughes, TR; Emili, A; Buratowski, S; Hieter, P; Greenblatt, JF
NuA4, the only essential histone acetyltransferase complex in Saccharomyces cerevisiae, acetylates the N-terminal tails of histones H4 and H2A. Affinity purification of NuA4 revealed the presence of three previously undescribed subunits, Vid2l/Eaf1/Ydr359c, Swc4/Eaf2/Ygr002c, and Eaf7/Ynl136w. Experimental analyses revealed at least two functionally distinct sets of polypeptides in NuA4: (i) Vid21 and Yng2, and (ii) Eaf5 and Eaf7. Vid21 and Yng2 are required for bulk histone H4 acetylation and are functionally linked to the histone H2A variant Htz1 and the Swr1 ATPase complex (SWR-C) that assembles Htz1 into chromatin, whereas Eaf5 and Eaf7 have a different, as yet undefined, role. Mutations in Htz1, the SWR-C, and NuA4 cause defects in chromosome segregation that are consistent with genetic interactions we have observed between the genes encoding these proteins and genes encoding kinetochore components. Because SWR-C-dependent recruitment of Htz1 occurs in both transcribed and centromeric regions, a NuA4/SWR-C/Htz1 pathway may regulate both transcription and centromere function in S. cerevisiae.