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Molecular and cytological characterization of SspI-family repetitive sequence on the chicken W chromosome
被引:39
作者:
Itoh, Y
Mizuno, S
机构:
[1] Nihon Univ, Dept Agr & Biol Chem, Coll Bioresource Sci, Fujisawa, Kanagawa 2528510, Japan
[2] Tohoku Univ, Mol Biol Lab, Dept Mol & Cell Biol, Grad Sch Agr Sci,Aoba Ku, Sendai, Miyagi 9818555, Japan
基金:
日本学术振兴会;
关键词:
chicken;
chromomere;
lampbrush chromosome;
repetitive sequence;
W chromosome;
D O I:
10.1023/A:1020944414750
中图分类号:
Q5 [生物化学];
Q7 [分子生物学];
学科分类号:
071010 ;
081704 ;
摘要:
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. Agenomic clone, pWPRS09, containing a 508-bp Ssp I 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 degreesC. 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.
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页码:499 / 511
页数:13
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