title: Two X family DNA polymerases, lambda and mu, in meiotic tissues of the basidiomycete, Coprinus cinereus.
abstract: The X family DNA polymerases lambda (CcPollambda) and mu (CcPolmu) were shown to be expressed during meiotic prophase in the basidiomycete, Coprinus cinereus. These two polymerases are the only members of the X family in the C. cinereus genome. The open reading frame of CcPollambda encoded a predicted product of 800 amino acid residues and that of CcPolmicro of 621 amino acid residues. Both CcPollambda and CcPolmicro required Mn(2+) ions for activity, and both were strongly inhibited by dideoxythymidine triphosphate. Unlike their mammalian counterparts, CcPollambda and CcPolmicro had no terminal deoxynucleotidyl transferase activity. Immunostaining analysis revealed that CcPollambda was present at meiotic prophase nuclei in zygotene and pachytene cells, which is the period when homologous chromosomes pair and recombine. CcPolmicro was present in a slightly wider range of cell stages, zygotene to diplotene. In analyses using D-loop recombination intermediate substrates, we found that both CcPollambda and CcPolmicro could promote primer extension of an invading strand in a D-loop structure. Moreover, both polymerases could fully extend the primer in the D-loop substrate, suggesting that D-loop extension is an activity intrinsic to CcPollambda and CcPolmicro. Based on these data, we discuss the possible roles of these polymerases in meiosis.
authors.affiliation: Department of Applied Biological Science, Tokyo University of Science, 2641 Yamazaki, Noda-shi, Chiba-ken 278-8510, Japan.
authors.forename: Aiko
authors.initials: A
authors.lastname: Sakamoto
authors.forename: Kazuki
authors.initials: K
authors.lastname: Iwabata
authors.forename: Akiyo
authors.initials: A
authors.lastname: Koshiyama
authors.forename: Hiroko
authors.initials: H
authors.lastname: Sugawara
authors.forename: Takuro
authors.initials: T
authors.lastname: Yanai
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kanai
authors.forename: Ryo
authors.initials: R
authors.lastname: Takeuchi
authors.forename: Yoko
authors.initials: Y
authors.lastname: Daikuhara
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Takakusagi
authors.forename: Kengo
authors.initials: K
authors.lastname: Sakaguchi
mesh_terms: D000595:Amino Acid Sequence; D003302:Coprinus / Q000201:enzymology* / Q000235:genetics; D019951:DNA Polymerase beta / Q000235:genetics*; D004259:DNA-Directed DNA Polymerase / Q000235:genetics*; D006801:Humans; D008540:Meiosis / Q000235:genetics*; D008969:Molecular Sequence Data; D011418:Prophase / Q000235:genetics
chemical_list: C415367:DNA polymerase beta2; C407743:DNA polymerase mu; D019951:DNA Polymerase beta; D004259:DNA-Directed DNA Polymerase