RAPID, LOCALIZED AMPLIFICATION OF A UNIQUE SATELLITE DNA FAMILY IN THE RODENT MICROTUS-CHROTORRHINUS
RAPID, LOCALIZED AMPLIFICATION OF A UNIQUE SATELLITE DNA FAMILY IN THE RODENT MICROTUS-CHROTORRHINUS
复制标题
DOI：
10.1007/bf00357104
复制
发表时间：
1993-07-01
期刊：
影响因子：
1.6
通讯作者：
MODI, WS
中科院分区：
文献类型：
--
作者：
MODI, WS
从嗜铬鼠中分离并鉴定了一个新的卫星DNA家族(命名为MSAT-2570)。该重复序列长度为2570bp，是迄今报道的哺乳动物中最大的重复序列之一，由一系列短的正向和反向重复序列组成。这些重复基序可能会阻止核小体的形成，或者代表着遗传变异的无尽来源。用HpaII/MspI和MboI/Sau3AI两对同裂异构体进行限制性内切酶消化，发现了卫星DNA甲基化的组织特异性差异，这可能反映了染色质构象的变化或基因表达模式的差异。在哺乳动物中，嗜铬分枝杆菌的性染色体非常大，占核型的15%-20%，并含有大块的异染色质。卫星DNA原位杂交显示，染色体定位以性染色体异染色质为主。对相关啮齿动物的调查表明，MSAT-2570只存在于嗜铬鼠的基因组中，其中包括三个同样具有巨大性染色体的同类物种。然而，此前报道的另一种也分离自嗜铬杆菌的卫星DNA已被证明位于其他三个物种的性染色体异染色质上，这表明这些异染色质的巨型块结构复杂，由多个无关的卫星DNA家族组成。
A novel satellite DNA family (called MSAT-2570) was isolated and characterized from the rodent Microtus chrotorrhinus. With a length of 2,570 bp the repeat unit is among the largest yet reported in mammals and comprises a series of short direct and inverted repeats. These repeat motifs may prevent nucleosome formation or represent an endless source of genetic variation. Restriction enzyme digestion using the two pairs of isoschizomers HpaII/MspI and MboI/Sau3AI demonstrated tissue specific differences in satellite DNA methylation that may reflect variable chromatin conformation or differences in patterns of gene expression. The sex chromosomes of M. chrotorrhinus are unusually large in size among mammals, comprising 15%-20% of the karyotype and containing large blocks of heterochromatin. In situ hybridization of the satellite DNA revealed chromosomal localization predominantly to sex chromosome heterochromatin. A survey of related rodents including three congeneric species also with giant sized sex chromosomes demonstrated that MSAT-2570 is present only in the genome of M. chrotorrhinus. However, another previously reported satellite DNA also isolated from M. chrotorrhinus has been shown to reside on sex chromosome heterochromatin in one of the other three species, indicating that these giant blocks of heterochromatin are complex in structure and comprise multiple, unrelatined satellite DNA families.