Alternative titles; symbols
HGNC Approved Gene Symbol: CHRAC1
Cytogenetic location: 8q24.3 Genomic coordinates (GRCh38): 8:140,511,322-140,517,154 (from NCBI)
CHRAC1 is a histone-fold protein that interacts with other histone-fold proteins to bind DNA in a sequence-independent manner. These histone-fold protein dimers combine within larger enzymatic complexes for DNA transcription, replication, and packaging.
Poot et al. (2000) identified CHRAC1, which they designated CHRAC15, or p15, within a chromatin remodeling complex, CHRAC, purified from HeLa cell nuclear extracts. The protein contains 131 amino acids and shows an apparent molecular mass of 15 kD by SDS-PAGE. The putative histone-fold domain of CHRAC1 has similarity to the H2A-type histone-fold domain of CBFC (NFYC; 605344). Northern blot analysis revealed variable but ubiquitous expression of a 2.4-kb transcript that paralleled the expression of another histone-fold protein, CHRAC17 (POLE3; 607267).
Bolognese et al. (2000) cloned mouse Chrac1, which they designated Ycl1. The deduced 129-amino acid protein is highly acidic and contains a short N terminus, a central 65-amino acid histone-fold motif, and a short C terminus that is rich in lysine and acidic residues. The authors noted that there is a high degree of phylogenetic conservation that extends beyond the histone-fold motif. Northern blot analysis revealed expression of a 1.2-kb transcript in all mouse cell lines tested.
Poot et al. (2000) affinity purified a human chromatin remodeling complex, CHRAC, from HeLa cell nuclear extracts using antibody that cross-reacts with the SNF2H (SMARCA5; 603375) and SNF2L (see 300012) isoforms of human ISWI but does not distinguish between them. POLE3, CHRAC1, and BAZ1A (605680), which the authors called ACF1, coimmunoprecipitated within this ISWI-containing complex, and the authors determined that the complex contains predominantly the SNF2H isoform of ISWI. Using pull-down assays with recombinant proteins, Poot et al. (2000) found that POLE3 and CHRAC1 interact directly with each other, and they concluded that the H2B-type histone-fold domain of POLE3 likely interacts with the H2A-type histone-fold domain of CHRAC1. They confirmed high-affinity DNA-binding activity for the POLE3-CHRAC1 complex, with a dissociation constant in the submicromolar range. POLE3 and CHRAC1 did not interact individually with DNA, and the POLE3-CHRAC1 complex did not interact well with nucleosomes.
Using an in vitro protein-protein interaction assay between recombinant mouse proteins and nuclear extracts, Bolognese et al. (2000) confirmed heterodimerization between Pole3 and Chrac1. In nucleosome reconstitution assays, the Pole3-Chrac1 dimer formed complexes with histones in solution and on DNA.
Based on sequence similarity to an EST (GenBank AI931369), Bolognese et al. (2000) mapped the CHRAC1 gene to chromosome 8q11-q12.
Bolognese, F., Imbriano, C., Caretti, G., Mantovani, R. Cloning and characterization of the histone-fold proteins YBL1 and YCL1. Nucleic Acids Res. 28: 3830-3838, 2000. [PubMed: 11000277] [Full Text: https://doi.org/10.1093/nar/28.19.3830]
Poot, R. A., Dellaire, G., Hulsmann, B. B., Grimaldi, M. A., Corona, D. F. V., Becker, P. B., Bickmore, W. A., Varga-Weisz, P. D. HuCHRAC, a human ISWI chromatin remodelling complex contains hACF1 and two novel histone-fold proteins. EMBO J. 19: 3377-3387, 2000. [PubMed: 10880450] [Full Text: https://doi.org/10.1093/emboj/19.13.3377]