This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Glowczewski, L. Articles by Berman, J. G. Search for Related Content PubMed PubMed Citation Articles by Glowczewski, L. Articles by Berman, J. G.

 Previous Article  |  Next Article 

Molecular and Cellular Biology, December 2004, p. 10180-10192, Vol. 24, No. 23
0270-7306/04/$08.00+0     DOI: 10.1128/MCB.24.23.10180-10192.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.

Yeast Chromatin Assembly Complex 1 Protein Excludes Nonacetylatable Forms of Histone H4 from Chromatin and the Nucleus

Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota,¹ Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri—Kansas City, Kansas City, Missouri²

Received 6 April 2004/ Returned for modification 3 May 2004/ Accepted 2 September 2004

In yeast, the establishment and maintenance of a transcriptionally silent chromatin state are dependent upon the acetylation state of the N terminus of histone proteins. Histone H4 proteins that contain mutations in N-terminal lysines disrupt heterochromatin and result in yeast that cannot mate. Introduction of a wild-type copy of histone H4 restores mating, despite the presence of the mutant protein, suggesting that mutant H4 protein is either excluded from, or tolerated in, chromatin. To understand how the cell differentiates wild-type histone and mutant histone in which the four N-terminal lysines were replaced with alanine (H4-4A), we analyzed silencing, growth phenotypes, and the histone composition of chromatin in yeast strains coexpressing equal amounts of wild-type and mutant H4 proteins (histone H4 heterozygote). We found that histone H4 heterozygotes have defects in heterochromatin silencing and growth, implying that mutations in H4 are not completely recessive. Nuclear preparations from histone H4 heterozygotes contained less mutant H4 than wild-type H4, consistent with the idea that cells exclude some of the mutant histone. Surprisingly, the N-terminal nuclear localization signal of H4-4A fused to green fluorescent protein was defective in nuclear localization, while a mutant in which the four lysines were replaced with arginine (H4-4R) appeared to have normal nuclear import, implying a role for the charged state of the acetylatable lysines in the nuclear import of histones. The biased partial exclusion of H4-4A was dependent upon Cac1p, the largest subunit of yeast chromatin assembly factor 1 (CAF-1), as well as upon the karyopherin Kap123p, but was independent of Cac2p, another CAF-1 component, and other chromatin assembly proteins (Hir3p, Nap1p, and Asf1p). We conclude that N-terminal lysines of histone H4 are important for efficient histone nuclear import. In addition, our data support a model whereby Cac1p and Kap123 cooperate to ensure that only appropriately acetylated histone H4 proteins are imported into the nucleus.

This article has been cited by other articles:

• Finley, K. R., Bouchonville, K. J., Quick, A., Berman, J. (2008). Dynein-dependent nuclear dynamics affect morphogenesis in Candida albicans by means of the Bub2p spindle checkpoint. J. Cell Sci. 121: 466-476 [Abstract] [Full Text]  
• Blackwell, J. S. Jr., Wilkinson, S. T., Mosammaparast, N., Pemberton, L. F. (2007). Mutational Analysis of H3 and H4 N Termini Reveals Distinct Roles in Nuclear Import. J. Biol. Chem. 282: 20142-20150 [Abstract] [Full Text]  
• Benson, L. J., Phillips, J. A., Gu, Y., Parthun, M. R., Hoffman, C. S., Annunziato, A. T. (2007). Properties of the Type B Histone Acetyltransferase Hat1: H4 TAIL INTERACTION, SITE PREFERENCE, AND INVOLVEMENT IN DNA REPAIR. J. Biol. Chem. 282: 836-842 [Abstract] [Full Text]  
• Adkins, M. W., Carson, J. J., English, C. M., Ramey, C. J., Tyler, J. K. (2007). The Histone Chaperone Anti-silencing Function 1 Stimulates the Acetylation of Newly Synthesized Histone H3 in S-phase. J. Biol. Chem. 282: 1334-1340 [Abstract] [Full Text]  
• Timney, B. L., Tetenbaum-Novatt, J., Agate, D. S., Williams, R., Zhang, W., Chait, B. T., Rout, M. P. (2006). Simple kinetic relationships and nonspecific competition govern nuclear import rates in vivo. J. Cell Biol. 175: 579-593 [Abstract] [Full Text]  
• Benson, L. J., Gu, Y., Yakovleva, T., Tong, K., Barrows, C., Strack, C. L., Cook, R. G., Mizzen, C. A., Annunziato, A. T. (2006). Modifications of H3 and H4 during Chromatin Replication, Nucleosome Assembly, and Histone Exchange. J. Biol. Chem. 281: 9287-9296 [Abstract] [Full Text]  
• Harkness, T. A. A., Arnason, T. G., Legrand, C., Pisclevich, M. G., Davies, G. F., Turner, E. L. (2005). Contribution of CAF-I to Anaphase-Promoting-Complex-Mediated Mitotic Chromatin Assembly in Saccharomyces cerevisiae. Eukaryot Cell 4: 673-684 [Abstract] [Full Text]