Comparative analyses of heterochromatin in Microtus: sequence heterogeneity and localized expansion and contraction of satellite DNA arrays.
Comparative analyses of heterochromatin in Microtus: sequence heterogeneity and localized expansion and contraction of satellite DNA arrays.
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田鼠异染色质的比较分析：序列异质性和卫星 DNA 阵列的局部扩张和收缩。
DOI：
10.1159/000133458
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Modi,WS
中科院分区：
文献类型：
--
作者：
Modi,WS
采用Southern杂交、C-显带、碱基特异性荧光染色和荧光原位杂交等方法，对田鼠属8种和8亚种鼠类的组成型异染色质进行了分析。常染色体着丝粒区在C带阳性物质的存在量方面表现出物种之间的相当大的变异性;例如，染色支原体染色相对较少，而金黄支原体则表现出广泛的着丝粒染色。在Guentheri和M. ochrogaster的两个亚种中观察到自体间质C带。所有的Y染色体都是异染色质的，在三个物种（M.agrestis，M. cabresticus和M. chrotorpheus）中，巨大的X染色体的相当大的部分也是异染色质的。Hoechst 33258染色（对AT结合位点具有亲和力）显示，在M. agrestis的性染色体异染色质上有明亮的荧光，而在M. cabrera和M. chrotoranus的性染色体上有中等的荧光;然而，只有M. cabrera和M. chrotoranus的异染色质与从M. chrotoranus分离的富含AT的卫星DNA探针（MSAT-160）杂交。禾谷缢管蚜和甘蓝缢管蚜的Hoechst 33258-bright常染色体着丝粒也与探针杂交，而禾谷缢管蚜和根特缢管蚜的Hoechst 33258-bright Y染色体则不与探针杂交。根据C-分带、Hoechst 33258染色、色霉素A3/偏端霉素A染色和原位杂交结果，发现冈瑟氏分枝杆菌的两对常染色体由6个不同的区域组成。近端着丝粒常染色体的着丝粒区保留保守的G带模式，可能会表现出不同的杂交强度时，不同的物种或亚种进行比较。M.ochrogasterportrays相当大的亚种间变异的大小和常染色体端粒和间质C带的位置，也是杂交的网站。这后两个发现表明，显着差异的拷贝数的串联卫星阵列可以存在于同源染色体的位置内和物种之间。
Southern blotting, C-banding, base-specific fluorochrome staining, and fluorescence in situ hybridization were used to analyze the constitutive heterochromatin in eight species and subspecies of arvicolid rodents (genusMicrotus). Autosomal centromeric regions portrayed considerable variability between species in the amount of C-band-positive material present; e.g.,M.chrotorrhinusshowed relatively little, whereasM.cabreraeexhibited extensive centromeric staining. Autoso-mal interstitial C-bands were noted inM.guentheriand two subspecies ofM.ochrogaster. All Y chromosomes examined were predominately or completely heterochromatic, as were substantial portions of the giant X chromosomes in three species(M.agrestis, M.cabrerae,andM.chrotorrhinus). Hoechst 33258 staining (with its affinity for AT binding sites) showed bright fluorescence on the heterochromatin of the sex chromosomes ofM.agrestisand moderate fluorescence on those ofM.cabreraeandM.chrotorrhinus;however, only the heterochromatin ofM.cabreraeandM.chrotorrhinushybridized with an AT-rich satellite DNA probe (MSAT-160) isolated fromM.chrotorrhinus. Hoechst 33258-bright autosomal centromeres ofM.arvalisandM.cabreraealso hybridized to the probe, whereas the Hoechst 33258-bright Y chromosomes ofM.arvalisandM.guentheridid not. Two pairs of autosomes inM.guentheriare comprised of six distinct regions, based upon C-banding, Hoechst 33258 staining, chromomycin A3/distamy-cin A staining, and in situ hybridization. The centromeric regions of acrocentric autosomes known to retain conserved G-banding patterns may exhibit variable hybridization intensity when different species or subspecies are compared.M.ochrogasterportrays considerable intersubspecific variability in the size and location of autosomal telomeric and interstitial C-bands that are also sites of hybridization. These latter two findings illustrate that dramatic differences in copy number of the tandem satellite array can exist at homologous chromosomal positions both within and between species.