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Type B histone acetyltransferase Hat1p participates in telomeric silencing.
- Source :
-
Molecular and cellular biology [Mol Cell Biol] 2000 Oct; Vol. 20 (19), pp. 7051-8. - Publication Year :
- 2000
-
Abstract
- Hat1p and Hat2p are the two subunits of a type B histone acetyltransferase from Saccharomyces cerevisiae that acetylates free histone H4 on lysine 12 in vitro. However, the role for these gene products in chromatin function has been unclear, as deletions of the HAT1 and/or HAT2 gene displayed no obvious phenotype. We have now identified a role for Hat1p and Hat2p in telomeric silencing. Telomeric silencing is the transcriptional repression of telomere-proximal genes and is mediated by a special chromatin structure. While there was no change in the level of silencing on a telomeric gene when the HAT1 or HAT2 gene was deleted, a significant silencing defect was observed when hat1Delta or hat2Delta was combined with mutations of the histone H3 NH(2)-terminal tail. Specifically, when at least two lysine residues were changed to arginine in the histone H3 tail, a hat1Delta-dependent telomeric silencing defect was observed. The most dramatic effects were seen when one of the two changes was in lysine 14. In further analysis, we found that a single lysine out of the five in the histone H3 tail was sufficient to mediate silencing. However, K14 was the best at preserving silencing, followed by K23 and then K27; K9 and K18 alone were insufficient. Mutational analysis of the histone H4 tail indicated that the role of Hat1p in telomeric silencing was mediated solely through lysine 12. Thus, in contrast to other histone acetyltransferases, Hat1p activity was required for transcriptional repression rather than gene activation.
- Subjects :
- Acetylation
Acetyltransferases genetics
Amino Acid Substitution
Chromatin metabolism
Fungal Proteins genetics
Gene Deletion
Heterochromatin metabolism
Histone Acetyltransferases
Mutation, Missense
Protein Processing, Post-Translational
Saccharomyces cerevisiae genetics
Transcription, Genetic
Transcriptional Activation
Acetyltransferases physiology
Fungal Proteins physiology
Gene Expression Regulation, Fungal
Gene Silencing
Histones metabolism
Saccharomyces cerevisiae enzymology
Saccharomyces cerevisiae Proteins
Telomere metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0270-7306
- Volume :
- 20
- Issue :
- 19
- Database :
- MEDLINE
- Journal :
- Molecular and cellular biology
- Publication Type :
- Academic Journal
- Accession number :
- 10982821
- Full Text :
- https://doi.org/10.1128/MCB.20.19.7051-7058.2000