Highly repetitive DNA families restricted to germ cells in a Japanese hagfish (Eptatretus burgeri):: a hierarchical and mosaic structure in eliminated chromosomes
Highly repetitive DNA families restricted to germ cells in a Japanese hagfish (Eptatretus burgeri):: a hierarchical and mosaic structure in eliminated chromosomes
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DOI：
10.1023/a:1013751600787
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发表时间：
2001-01-01
期刊：
影响因子：
1.5
通讯作者：
Kohno, S
中科院分区：
文献类型：
--
作者：
Kubota, S;Takano, J;Kohno, S
已知八目鳗类的染色体消除发生在胚胎发育早期。被淘汰的染色体大多是C带阳性的，因此没有任何体细胞具有任何C带阳性染色质。近年来，利用分子生物学的方法，发现了一些高重复DNA序列作为这些盲鳗的淘汰因子。然而，没有生殖系限制的重复DNA已被直接从日本八目鳗Eptatretus burgeri，其中约21%的总DNA被排除从推定的体细胞。通过限制性内切酶酶切后的电泳分析，分离到两个仅限于生殖系DNA的DNA家族。分子克隆和序列分析表明，这些家庭是由64和57 bp的长度分别密切相关的序列。Southern杂交结果表明，这两个DNA家族仅限于生殖系DNA，因此分别命名为EEEb 1和EEEb 2。此外，这些消除的元素是高度和串联重复，它是预测，他们可能会通过跳跃式复制扩增，并以协调一致的方式进化。密度扫描结果表明，EEEb 1和EEEb 2分别占总基因组DNA的18.5%和0.024%，占总消除DNA的88.6%。荧光原位杂交结果表明，EEEb 1定位于所有生殖细胞的C带阳性染色体上，表明EEEb 1是大肠杆菌DNA消除的主要成分。汉堡
It is known that in eight hagfishes chromosome elimination occurs during early embryogenesis. The eliminated chromosomes are mostly C-band positive, so that none of the somatic cells have any C-band-positive chromatin. Recently, some highly repetitive DNA sequences have been reported as eliminated elements in these hagfishes based on molecular biological methods. However, no germline-restricted repetitive DNA have been directly isolated from the Japanese hagfish Eptatretus burgeri, from which approximately 21% of the total DNA is eliminated from presumptive somatic cells. Through electrophoretic investigation after digestion with restriction endonucleases, two DNA families that are restricted to germline DNA were isolated. Molecular cloning and sequence analysis revealed that these families are composed of closely related sequences of 64 and 57 bp in length, respectively. Southern blot hybridization revealed that the two DNA families are restricted to germline DNA and were thus named EEEb1 and EEEb2, respectively. Moreover, these eliminated elements were highly and tandemly repeated, and it is predicted that they might amplify by saltatory replication and have evolved in a concerted manner. By densitometric scanning, EEEb1 and EEEb2 were found to amount to make up approximately 18.5 and 0.024% of the total germline genomic DNA, accounting for 88.6% of the total eliminated DNA. A fluorescence in situ hybridization experiment demonstrated that EEEb1 is located on all C-band-positive chromosomes that are limited to germ cells, suggesting that EEEb1 is the primary component of eliminated DNA of E. burgeri.