title: Transcription initiation factor IID-interactive histone chaperone CIA-II implicated in mammalian spermatogenesis.
abstract: Histones are thought to have specific roles in mammalian spermatogenesis, because several subtypes of histones emerge that are post-translationally modified during spermatogenesis. Though regular assembly of nucleosome is guaranteed by histone chaperones, their involvement in spermatogenesis is yet to be characterized. Here we identified a histone chaperone-related factor, which we designated as CCG1-interacting factor A-II (CIA-II), through interaction with bromodomains of TAFII250/CCG1, which is the largest subunit of human transcription initiation factor IID (TFIID). We found that human CIA-II (hCIA-II) localizes in HeLa nuclei and is highly expressed in testis and other proliferating cell-containing tissues. Expression of mouse CIA-II (mCIA-II) does not occur in the germ cell-lacking testes of adult WBB6F1-W/Wv mutant mice, indicating its expression in testis to be specific to germ cells. Fractionation of testicular germ cells revealed that mCIA-II transcripts accumulate in pachytene spermatocytes but not in spermatids. In addition, the mCIA-II transcripts in testis were present as early as 4 days after birth and decreased at 56 days after birth. These findings indicate that mCIA-II expression in testis is restricted to premeiotic to meiotic stages during spermatogenesis. Also, we found that hCIA-II interacts with histone H3 in vivo and with histones H3/H4 in vitro and that it facilitates supercoiling of circular DNA when it is incubated with core histones and topoisomerase I in vitro. These data suggest that CIA-II is a histone chaperone and is implicated in the regulation of mammalian spermatogenesis.
authors.affiliation: Laboratory of Developmental Biology, Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Umehara
authors.forename: Masami
authors.initials: M
authors.lastname: Horikoshi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone; D003001:Cloning, Molecular; D006657:Histones / Q000378:metabolism*; D006801:Humans; D008297:Male; D008322:Mammals; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009707:Nucleosomes / Q000502:physiology; D011994:Recombinant Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013091:Spermatogenesis / Q000502:physiology*; D035362:Transcription Factor TFIID / Q000378:metabolism*
chemical_list: C109731:ASF1 protein, S cerevisiae; C491641:ASF1A protein, human; C491640:ASF1B protein, human; C491639:Asf1b protein, mouse; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D006657:Histones; D018832:Molecular Chaperones; D009707:Nucleosomes; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D035362:Transcription Factor TFIID