Analysis of histones from the yeast Saccharomyces carlsbergensis (original) (raw)
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Histone modifications in the yeast S. cerevisiae
Nucleic Acids Research, 1981
The content of the acetylated histone species associated with the highly transcriptionally active chromatin of yeast was examined. We found yeast chromatin to contain very high levels of the acetylated species for histones H3, H4 and possibly the H2B variants, H2B-1 and H2B-2. Sixty-three percent of the histone H4 species was represented by the di-, triand tetra-acetylated forms. These results make yeast chromatin among the most highly acetylated of any chromatins reported thus far. In addition, the results are consistent with the idea that hyperacetylation of histones allows chromatin to be transcribed at an increased rate.
Yeast inner histones and the evolutionary conservation of histone-histone interactions
Biochemistry, 1978
The inner histones of the yeast, Saccharomyces cereuisiae, have been isolated and identified by their amino acid compositions. H4 appears to be close to its calf and pea counterparts. H2a, H2b, and H3 have diverged. The isolation of the histones was accomplished by consecutive slab-gel fractionation, and a number of novel features of the method s t u d i e s on the histones of Saccharomyces cereuisiae, the common baker's yeast, began more than 10 years ago (Tonino
The regulation of euchromatin and heterochromatin by histones in yeast
Journal of Cell Science, 1995
SUMMARY Yeast chromosomes may lack the linker histone H1 (normally required to compact 10 nm beads-on-a-string fiber into the 30 nm fiber) and there is no cytological evidence for higher order fiber structure but they do contain regions which correspond to euchromatin and heterochromatin of higher eukaryotes. Both euchromatin and heterochromatin contain nucleosomal particles (composed of two molecules each of histones H2A, H2B, H3 and H4), however histones have been shown to regulate genes in these regions in quite different ways. The mechanisms by which such regulation occurs are the topic of this paper.
Molecular and Cellular Biology, 1993
The products of the HIRI and HIR2 genes have been defined genetically as repressors of histone gene transcription in S. cerevisiae. A mutation in either gene affects cell cycle regulation of three of the four histone gene loci; transcription of these loci occurs throughout the cell cycle and is no longer repressed in response to the inhibition of DNA replication. The same mutations also eliminate autogenous regulation of the HTA1-HTB1 locus by histones H2A and H2B. The HIR1 and HIR2 genes have been isolated, and their roles in the transcriptional regulation of the HTA1-HTB1 locus have been characterized. Neither gene encodes an essential protein, and null alleles derepress HTA1-HTB1 transcription. Both HIR genes are expressed constitutively under conditions that lead to repression or derepression of the HTAI gene, and neither gene regulates the expression of the other. The sequence of the HIR1 gene predicts an 88-kDa protein with three repeats of a motif found in the G. subunit of retinal transducin and in a yeast transcriptional repressor, Tupl. The sequence of the HIR2 gene predicts a protein of 98 kDa. Both gene products contain nuclear targeting signals, and the Hir2 protein is localized in the nucleus.
Journal of Biological Chemistry, 1998
We have analyzed the histone acetyltransferase enzymes obtained from a series of yeast hat1, hat2, and gcn5 single mutants and hat1,hat2 and hat1,gcn5 double mutants. Extracts prepared from both hat1 and hat2 mutant strains specifically lack the following two histone acetyltransferase activities: the well known cytoplasmic type B enzyme and a free histone H4-specific histone acetyltransferase located in the nucleus. The catalytic subunits of both cytoplasmic and nuclear enzymes have identical molecular masses (42 kDa), the same as that of HAT1. However, the cytoplasmic complex has a molecular mass (150 kDa) greater than that of the nuclear complex (110 kDa). The possible functions of HAT1 and HAT2 in the yeast nucleus are discussed. In addition, we have detected a yeast histone acetyltransferase not previously described, designated HAT-A4. This enzyme is located in the nucleus and is able to acetylate free and nucleosome-bound histones H3 and H4. Finally, we show that the hat1,gcn5 double mutant is viable and does not exhibit a new phenotype, thus suggesting the existence of several histone acetyltransferases with overlapping functions.
Is there a linker histone in the yeast Kluyveromyces lactis?
2011
In all eukaryotic cells nuclear DNA is organized in a highly-ordered nucleoprotein complex called chromatin. Along with DNA, essential structural and functional components of chromatin are histone proteins: core histones and linker histones. The latter are involved in both the maintenance of higher chromatin structures and together with core histones in regulation of gene expression. It has to be mentioned, however, that both functions of linker histones are more presumed than proved and therefore are subject of disputes.