title: Molecular and cytological characterization of SspI-family repetitive sequence on the chicken W chromosome.
abstract: A genomic clone, pWS44, isolated from the chicken W chromosome-specific genomic library contained a partial (226-bp) sequence of a novel SspI-family repetitive sequence. A genomic clone, pWPRS09, containing a 508-bp SspI fragment (a repeating unit of the family) was subsequently obtained and sequenced. This 0.5-kb unit is tandemly repeated about 11,300 times. FISH to mitotic and lampbrush W chromosomes indicates that the SspI-family is located on the chromomere 6 between heterochromatic and distal non-heterochromatic regions on the short arm. The SspI-family sequence was proved to be a good positional marker in FISH mapping of active genes in the non-heterochromatic region on the lampbrush W chromosome. The presence of SspI-family repetitive sequence is limited to the genus Gallus (chickens and jungle fowls). The 0.5-kb repeating unit contains a 120-bp stretch of polypurine/polypyrimidine sequence (GGAGA repeats), shows no DNA curvature, and rapid electrophoretic mobility in 4% polyacrylamide gel at 4 degrees C. The SspI-family forms a relatively diffused chromatin structure in nuclei. These features are distinctly different from those of XhoI- and EcoRI-family sequences on the W chromosome. The total amount of non-repetitive DNA in the chicken W chromosome is estimated to be about 10 Mb.
authors.affiliation: Laboratory of Molecular Biology, Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Itoh
authors.forename: Shigeki
authors.initials: S
authors.lastname: Mizuno
mesh_terms: D000818:Animals; D001483:Base Sequence; D002645:Chickens / Q000235:genetics*; D002875:Chromosomes / Q000235:genetics*; D003001:Cloning, Molecular; D004247:DNA / Q000737:chemistry / Q000235:genetics*; D017931:DNA Primers / Q000737:chemistry; D015252:Deoxyribonucleases, Type II Site-Specific / Q000145:classification / Q000235:genetics*; D015698:Genomic Library; D008745:Methylation; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D016133:Polymerase Chain Reaction; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping
chemical_list: D017931:DNA Primers; D004247:DNA; C061568:endodeoxyribonuclease SspI; D015252:Deoxyribonucleases, Type II Site-Specific