scholarly journals The N-terminal domains of histones H3 and H4 are not necessary for chromatin assembly factor-1- mediated nucleosome assembly onto replicated DNA in vitro

2000 ◽  
Vol 97 (14) ◽  
pp. 7766-7771 ◽  
Author(s):  
K.-i. Shibahara ◽  
A. Verreault ◽  
B. Stillman
2007 ◽  
Vol 18 (1) ◽  
pp. 129-141 ◽  
Author(s):  
Yasunari Takami ◽  
Tatsuya Ono ◽  
Tatsuo Fukagawa ◽  
Kei-ichi Shibahara ◽  
Tatsuo Nakayama

Chromatin assembly factor-1 (CAF-1), a complex consisting of p150, p60, and p48 subunits, is highly conserved from yeast to humans and facilitates nucleosome assembly of newly replicated DNA in vitro. To investigate roles of CAF-1 in vertebrates, we generated two conditional DT40 mutants, respectively, devoid of CAF-1p150 and p60. Depletion of each of these CAF-1 subunits led to delayed S-phase progression concomitant with slow DNA synthesis, followed by accumulation in late S/G2 phase and aberrant mitosis associated with extra centrosomes, and then the final consequence was cell death. We demonstrated that CAF-1 is necessary for rapid nucleosome formation during DNA replication in vivo as well as in vitro. Loss of CAF-1 was not associated with the apparent induction of phosphorylations of S-checkpoint kinases Chk1 and Chk2. To elucidate the precise role of domain(s) in CAF-1p150, functional dissection analyses including rescue assays were preformed. Results showed that the binding abilities of CAF-1p150 with CAF-1p60 and DNA polymerase sliding clamp proliferating cell nuclear antigen (PCNA) but not with heterochromatin protein HP1-γ are required for cell viability. These observations highlighted the essential role of CAF-1–dependent nucleosome assembly in DNA replication and cell proliferation through its interaction with PCNA.


eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Paul Victor Sauer ◽  
Jennifer Timm ◽  
Danni Liu ◽  
David Sitbon ◽  
Elisabetta Boeri-Erba ◽  
...  

How the very first step in nucleosome assembly, deposition of histone H3-H4 as tetramers or dimers on DNA, is accomplished remains largely unclear. Here, we report that yeast chromatin assembly factor 1 (CAF1), a conserved histone chaperone complex that deposits H3-H4 during DNA replication, binds a single H3-H4 heterodimer in solution. We identify a new DNA-binding domain in the large Cac1 subunit of CAF1, which is required for high-affinity DNA binding by the CAF1 three-subunit complex, and which is distinct from the previously described C-terminal winged-helix domain. CAF1 binds preferentially to DNA molecules longer than 40 bp, and two CAF1-H3-H4 complexes concertedly associate with DNA molecules of this size, resulting in deposition of H3-H4 tetramers. While DNA binding is not essential for H3–H4 tetrasome deposition in vitro, it is required for efficient DNA synthesis-coupled nucleosome assembly. Mutant histones with impaired H3-H4 tetramerization interactions fail to release from CAF1, indicating that DNA deposition of H3-H4 tetramers by CAF1 requires a hierarchical cooperation between DNA binding, H3-H4 deposition and histone tetramerization.


2009 ◽  
Vol 29 (24) ◽  
pp. 6353-6365 ◽  
Author(s):  
Tom Rolef Ben-Shahar ◽  
Araceli G. Castillo ◽  
Michael J. Osborne ◽  
Katherine L. B. Borden ◽  
Jack Kornblatt ◽  
...  

ABSTRACT Chromatin assembly factor 1 (CAF-1) deposits histones H3 and H4 rapidly behind replication forks through an interaction with the proliferating cell nuclear antigen (PCNA), a DNA polymerase processivity factor that also binds to a number of replication enzymes and other proteins that act on nascent DNA. The mechanisms that enable CAF-1 and other PCNA-binding proteins to function harmoniously at the replication fork are poorly understood. Here we report that the large subunit of human CAF-1 (p150) contains two distinct PCNA interaction peptides (PIPs). The N-terminal PIP binds strongly to PCNA in vitro but, surprisingly, is dispensable for nucleosome assembly and only makes a modest contribution to targeting p150 to DNA replication foci in vivo. In contrast, the internal PIP (PIP2) lacks one of the highly conserved residues of canonical PIPs and binds weakly to PCNA. Surprisingly, PIP2 is essential for nucleosome assembly during DNA replication in vitro and plays a major role in targeting p150 to sites of DNA replication. Unlike canonical PIPs, such as that of p21, the two p150 PIPs are capable of preferentially inhibiting nucleosome assembly, rather than DNA synthesis, suggesting that intrinsic features of these peptides are part of the mechanism that enables CAF-1 to function behind replication forks without interfering with other PCNA-mediated processes.


1998 ◽  
Vol 143 (3) ◽  
pp. 563-575 ◽  
Author(s):  
Emmanuelle Martini ◽  
Danièle M.J. Roche ◽  
Kathrin Marheineke ◽  
Alain Verreault ◽  
Geneviève Almouzni

The subcellular distribution and posttranslational modification of human chromatin assembly factor 1 (CAF-1) have been investigated after UV irradiation of HeLa cells. In an asynchronous cell population only a subfraction of the two large CAF-1 subunits, p150 and p60, were found to exist in a chromatin-associated fraction. This fraction is most abundant during S phase in nonirradiated cells and is much reduced in G2 cells. After UV irradiation, the chromatin-associated form of CAF-1 dramatically increased in all cells irrespective of their position in the cell cycle. Such chromatin recruitment resembles that seen for PCNA, a DNA replication and repair factor. The chromatin-associated fraction of p60 was predominantly hypophosphorylated in nonirradiated G2 cells. UV irradiation resulted in the rapid recruitment to chromatin of phosphorylated forms of the p60 subunit. Furthermore, the amount of the p60 and p150 subunits of CAF-1 associated with chromatin was a function of the dose of UV irradiation. Consistent with these in vivo observations, we found that the amount of CAF-1 required to stimulate nucleosome assembly during the repair of UV photoproducts in vitro depended upon both the number of lesions and the phosphorylation state of CAF-1. The recruitment of CAF-1 to chromatin in response to UV irradiation of human cells described here supports a physiological role for CAF-1 in linking chromatin assembly to DNA repair.


2011 ◽  
Vol 194 (2) ◽  
pp. 229-243 ◽  
Author(s):  
Meghan C. Barnhart ◽  
P. Henning J. L. Kuich ◽  
Madison E. Stellfox ◽  
Jared A. Ward ◽  
Emily A. Bassett ◽  
...  

Centromeres of higher eukaryotes are epigenetically marked by the centromere-specific CENP-A nucleosome. New CENP-A recruitment requires the CENP-A histone chaperone HJURP. In this paper, we show that a LacI (Lac repressor) fusion of HJURP drove the stable recruitment of CENP-A to a LacO (Lac operon) array at a noncentromeric locus. Ectopically targeted CENP-A chromatin at the LacO array was sufficient to direct the assembly of a functional centromere as indicated by the recruitment of the constitutive centromere-associated network proteins, the microtubule-binding protein NDC80, and the formation of stable kinetochore–microtubule attachments. An amino-terminal fragment of HJURP was able to assemble CENP-A nucleosomes in vitro, demonstrating that HJURP is a chromatin assembly factor. Furthermore, HJURP recruitment to endogenous centromeres required the Mis18 complex. Together, these data suggest that the role of the Mis18 complex in CENP-A deposition is to recruit HJURP and that the CENP-A nucleosome assembly activity of HJURP is responsible for centromeric chromatin assembly to maintain the epigenetic mark.


2002 ◽  
Vol 22 (2) ◽  
pp. 614-625 ◽  
Author(s):  
Denise C. Krawitz ◽  
Tamar Kama ◽  
Paul D. Kaufman

ABSTRACT Chromatin assembly factor I (CAF-I) is a conserved histone H3/H4 deposition complex. Saccharomyces cerevisiae mutants lacking CAF-I subunit genes (CAC1 to CAC3) display reduced heterochromatic gene silencing. In a screen for silencing-impaired cac1 alleles, we isolated a mutation that reduced binding to the Cac3p subunit and another that impaired binding to the DNA replication protein PCNA. Surprisingly, mutations in Cac1p that abolished PCNA binding resulted in very minor telomeric silencing defects but caused silencing to be largely dependent on Hir proteins and Asf1p, which together comprise an alternative silencing pathway. Consistent with these phenotypes, mutant CAF-I complexes defective for PCNA binding displayed reduced nucleosome assembly activity in vitro but were stimulated by Asf1p-histone complexes. Furthermore, these mutant CAF-I complexes displayed a reduced preference for depositing histones onto newly replicated DNA. We also observed a weak interaction between Asf1p and Cac2p in vitro, and we hypothesize that this interaction underlies the functional synergy between these histone deposition proteins.


2019 ◽  
Vol 47 (21) ◽  
pp. 11114-11131 ◽  
Author(s):  
Liang Cheng ◽  
Xu Zhang ◽  
Yan Wang ◽  
Haiyun Gan ◽  
Xiaowei Xu ◽  
...  

Abstract Establishment and subsequent maintenance of distinct chromatin domains during embryonic stem cell (ESC) differentiation are crucial for lineage specification and cell fate determination. Here we show that the histone chaperone Chromatin Assembly Factor 1 (CAF-1), which is recruited to DNA replication forks through its interaction with proliferating cell nuclear antigen (PCNA) for nucleosome assembly, participates in the establishment of H3K27me3-mediated silencing during differentiation. Deletion of CAF-1 p150 subunit impairs the silencing of many genes including Oct4, Sox2 and Nanog as well as the establishment of H3K27me3 at these gene promoters during ESC differentiation. Mutations of PCNA residues involved in recruiting CAF-1 to the chromatin also result in defects in differentiation in vitro and impair early embryonic development as p150 deletion. Together, these results reveal that the CAF-1-PCNA nucleosome assembly pathway plays an important role in the establishment of H3K27me3-mediated silencing during cell fate determination.


2018 ◽  
Vol 46 (9) ◽  
pp. 4440-4455 ◽  
Author(s):  
Geetha S Hewawasam ◽  
Karthik Dhatchinamoorthy ◽  
Mark Mattingly ◽  
Chris Seidel ◽  
Jennifer L Gerton

Abstract Correct localization of the centromeric histone variant CenH3/CENP-A/Cse4 is an important part of faithful chromosome segregation. Mislocalization of CenH3 could affect chromosome segregation, DNA replication and transcription. CENP-A is often overexpressed and mislocalized in cancer genomes, but the underlying mechanisms are not understood. One major regulator of Cse4 deposition is Psh1, an E3 ubiquitin ligase that controls levels of Cse4 to prevent deposition into non-centromeric regions. We present evidence that Chromatin assembly factor-1 (CAF-1), an evolutionarily conserved histone H3/H4 chaperone with subunits shown previously to interact with CenH3 in flies and human cells, regulates Cse4 deposition in budding yeast. yCAF-1 interacts with Cse4 and can assemble Cse4 nucleosomes in vitro. Loss of yCAF-1 dramatically reduces the amount of Cse4 deposited into chromatin genome-wide when Cse4 is overexpressed. The incorporation of Cse4 genome-wide may have multifactorial effects on growth and gene expression. Loss of yCAF-1 can rescue growth defects and some changes in gene expression associated with Cse4 deposition that occur in the absence of Psh1-mediated proteolysis. Incorporation of Cse4 into promoter nucleosomes at transcriptionally active genes depends on yCAF-1. Overall our findings suggest CAF-1 can act as a CenH3 chaperone, regulating levels and incorporation of CenH3 in chromatin.


2004 ◽  
Vol 24 (11) ◽  
pp. 4710-4719 ◽  
Author(s):  
Renjie Jiao ◽  
Csanád Z. Bachrati ◽  
Graziella Pedrazzi ◽  
Patrick Kuster ◽  
Maja Petkovic ◽  
...  

ABSTRACT Bloom's syndrome (BS) is a genomic instability disorder characterized by cancer susceptibility. The protein defective in BS, BLM, belongs to the RecQ family of DNA helicases. In this study, we found that BLM interacts with hp150, the largest subunit of chromatin assembly factor 1 (CAF-1), in vitro and in vivo. Colocalization of a proportion of the cellular complement of these two proteins is found at specific nuclear foci coinciding with sites of DNA synthesis in the S phase. This colocalization increases in the presence of agents that damage DNA or inhibit DNA replication. In support of a functional interaction between BLM and CAF-1, we show that BLM inhibits CAF-1-mediated chromatin assembly during DNA repair in vitro. Although CAF-1 activity is not altered in BLM-deficient cells, the absence of BLM does impair the ability of CAF-1 to be mobilized within the nucleus in response to hydroxyurea treatment. Our results provide the first link between BLM and chromatin assembly coupled to DNA repair and suggest that BLM and CAF-1 function in a coordinated way to promote survival in response to DNA damage and/or replication blockade.


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