Poster: Evolution
Abs #
789: A bacterial artificial chromosome (BAC) library for Silene latifolia and identification of clones containing Y chromosome fragments
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Presenter: |
Sugiyama, Ryuji , sugiyama@biol.s.u-tokyo.ac.jp |
Authors | Sugiyama, Ryuji (A) Kazama, Yusuke (A) Uchida, Wakana (A) Matsunaga, Sachihiro (B) Kawano, Shigeyuki (A) | | Affiliations: |
(A): Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo
(B): Department of Biotechnology, Graduate School of Engineering, Osaka University
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Dioecy in the model dioecious plant Silene latifolia is determined genetically by its heteromorphic sex chromosomes. To reveal the plant Y chromosome structure and genes on the Y chromosome, a partial BAC library was constructed from the male plant. This BAC library contained 32,640 clones and the average insert size was 115 kb (0.8-fold coverage of the genome). Using STS markers, we screened a faction of the BAC library to isolate four BAC clones containing a Y chromosome fragment (#15B12, #9d12F, #15b4D, #23b9G) and one BAC clone containing an X chromosome fragment (#31d12A). #15B12 was selected for the following detail analysis. A portion of #19B12 was subcloned to construct the plasmid #25-1, with an insert of 7.8 kb. This 7.8-kb fragment encodes a homolog of Y-chromosome-specific sequence tagged site, ScD05, and a gene preferentially expressed in reproductive organs, CCLS96.1. The ScD05 homolog in #19B12 has two deletions, as compared to the Y-chromosome-specific ScD05. This indicated that there are at least two homologs located at different loci. RT-PCR showed sexually differential expression of CCLS96.1. The CCLS96.1 transcript showed higher accumulation in male flower buds than in male leaves, whereas it accumulated little in female flower buds. Rapid amplification of cDNA ends and RT-PCR produced at least six species of CCLS96.1 transcripts. However, from their sequences, no significant open reading frames could be predicted. The CCLS96.1 transcripts are expressed at the same level as the actin gene. Genomic Southern hybridization showed that the S.latifolia genome contains numerous CCLS96.1 homologs. We also discussed other clones containing Y chromosome fragments.
