Recent molecular cytogenetic studies demonstrate that extensive centromere-telomere fusions are the main chromosomal rearrangements underlying the karyotypic evolution of extant muntjacs. Although the molecular mechan...Recent molecular cytogenetic studies demonstrate that extensive centromere-telomere fusions are the main chromosomal rearrangements underlying the karyotypic evolution of extant muntjacs. Although the molecular mechanism of tandem fusions remains unknown, satellite DNA is believed to have facilitated chromosome fusions by non-allelic homologous recombination. Previous studies detected non-random hybridization signals of cloned satellite DNA at the postulated fusion sites on the chromosomes in Indian and Chinese muntjacs. But the genomic distribution and organization of satellite DNAs in other muntjacs have not been investigated. In this study, we have isolated four satellite DNA clones （BMCS, BM700, BM 1.1 k and FM700） from the black muntjac （Muntiacus crinifrons） and Fea＇s muntjac （M. feae）, and hybridized these four clones onto chromosomes of four muntjac species （M. reevesi, M. crinifrons, M. gongshanenisis and M. feae）. Besides the predominant centromeric signals, non-random interstitial hybridization signals from satellite I and II DNA clones （BMC5, BM700 and FM700） were also observed on the arms of chromosomes of these four muntjacs. Our results provide additional support for the notion that the karyotypes of M. crinifrons, M. feae and M. gongshanensis have evolved from a 2n = 70 ancestral karyotype by a series of chromosome fusions.展开更多
Cell lineages of nematodes are completely known: the adult male of Caenorhabditis elegans contains 1031 somatic cells, the hermaphrodite 959, not one more, not one less;cell divisions are strictly deterministic (as in...Cell lineages of nematodes are completely known: the adult male of Caenorhabditis elegans contains 1031 somatic cells, the hermaphrodite 959, not one more, not one less;cell divisions are strictly deterministic (as in the great majority of invertebrates) but so far nothing is known about the mechanism used by cells to count precise numbers of divisions. In vertebrates, each species has its invariable deterministic numbers of somites, vertebrae, fingers, and teeth: counting the number of iterations is a widespread process in living beings;nonetheless, it remains an unanswered question and a great challenge in cell biology. This paper introduces a computational model to investigate the possible role of satellite DNA in counting cell divisions, showing how cells may operate under Boolean logic algebra. Satellite DNA, made up of repeated monomers and subject to high epigenetic methylation rates, is very similar to iterable sequences used in programming: just like in the “iteration protocol” of algorithms, the epigenetic machinery may run over linear tandem repeats (that hold cell-fate data), read and orderly mark one monomer per cell-cycle (cytosine methylation), keep track and transmit marks to descendant cells, sending information to cell-cycle regulators.展开更多
The differences in satellite DNA methylation pattern of corn seedlings with various spontaneous chromosome aberration yields and changes in methylation pattern of these DNA sequences under different exposure modes of ...The differences in satellite DNA methylation pattern of corn seedlings with various spontaneous chromosome aberration yields and changes in methylation pattern of these DNA sequences under different exposure modes of acute UV-C and chronic gamma-irradiations have been investigated. The obtained experimental data and the conducted correlation analysis demonstrated the significant correlation between the satellite DNA methylation pattern varieties and chromosome aberration yields under various stress exposure modes. The role of satellite DNA methylation pattern variability and its changing in key responses to stress such as mobile elements’ activation, cell’s passage of checkpoints, and homological repair was discussed.展开更多
目的:对T细胞淋巴瘤(T-cell lymphoma,TCL)6号染色体上6个微卫星多态标志物进行等位基因杂合性缺失(loss of heterozygosity,LOH)分析,以明确该区域是否存在与人类TCL发生发展相关的抑癌基因。方法:选取6号染色体上6个微卫星多态标志D6S...目的:对T细胞淋巴瘤(T-cell lymphoma,TCL)6号染色体上6个微卫星多态标志物进行等位基因杂合性缺失(loss of heterozygosity,LOH)分析,以明确该区域是否存在与人类TCL发生发展相关的抑癌基因。方法:选取6号染色体上6个微卫星多态标志D6S251、D6S275、D6S287、D6S267、D6S262、D6S264,采用石蜡组织基因组DNA抽提、PCR扩增,变性聚丙烯酰胺凝胶垂直电泳、银染法分别检测了42例TCL中肿瘤组织与相应正常组织基因组DNA的LOH状况。结果:42例TCL中13例(13/42,30.95%)至少在1个位点出现LOH,以D6D262最高(10.3%),其次为D6S287(10.0%)和D6S267(7.3%)。而不同临床病理分型的TCL其LOH发生差异无统计学意义(P>0.05)。结论:在6号染色体上的6个微卫星标志中D6S287、D6S262和D6S267周围的6q21-6q23压域发生杂合性缺失率较高,位于6q21区编码Cyclin C的基因可能是此区与TCL发生发展相关的候选抑癌基因;尤其是6q21-6q22.1区域可能存在与TCL相关的抑癌基因,可能与TCL的发生发展有关。展开更多
基金the grant from the National Natural Science Foundation of China (30270719)
文摘Recent molecular cytogenetic studies demonstrate that extensive centromere-telomere fusions are the main chromosomal rearrangements underlying the karyotypic evolution of extant muntjacs. Although the molecular mechanism of tandem fusions remains unknown, satellite DNA is believed to have facilitated chromosome fusions by non-allelic homologous recombination. Previous studies detected non-random hybridization signals of cloned satellite DNA at the postulated fusion sites on the chromosomes in Indian and Chinese muntjacs. But the genomic distribution and organization of satellite DNAs in other muntjacs have not been investigated. In this study, we have isolated four satellite DNA clones （BMCS, BM700, BM 1.1 k and FM700） from the black muntjac （Muntiacus crinifrons） and Fea＇s muntjac （M. feae）, and hybridized these four clones onto chromosomes of four muntjac species （M. reevesi, M. crinifrons, M. gongshanenisis and M. feae）. Besides the predominant centromeric signals, non-random interstitial hybridization signals from satellite I and II DNA clones （BMC5, BM700 and FM700） were also observed on the arms of chromosomes of these four muntjacs. Our results provide additional support for the notion that the karyotypes of M. crinifrons, M. feae and M. gongshanensis have evolved from a 2n = 70 ancestral karyotype by a series of chromosome fusions.
文摘Cell lineages of nematodes are completely known: the adult male of Caenorhabditis elegans contains 1031 somatic cells, the hermaphrodite 959, not one more, not one less;cell divisions are strictly deterministic (as in the great majority of invertebrates) but so far nothing is known about the mechanism used by cells to count precise numbers of divisions. In vertebrates, each species has its invariable deterministic numbers of somites, vertebrae, fingers, and teeth: counting the number of iterations is a widespread process in living beings;nonetheless, it remains an unanswered question and a great challenge in cell biology. This paper introduces a computational model to investigate the possible role of satellite DNA in counting cell divisions, showing how cells may operate under Boolean logic algebra. Satellite DNA, made up of repeated monomers and subject to high epigenetic methylation rates, is very similar to iterable sequences used in programming: just like in the “iteration protocol” of algorithms, the epigenetic machinery may run over linear tandem repeats (that hold cell-fate data), read and orderly mark one monomer per cell-cycle (cytosine methylation), keep track and transmit marks to descendant cells, sending information to cell-cycle regulators.
文摘The differences in satellite DNA methylation pattern of corn seedlings with various spontaneous chromosome aberration yields and changes in methylation pattern of these DNA sequences under different exposure modes of acute UV-C and chronic gamma-irradiations have been investigated. The obtained experimental data and the conducted correlation analysis demonstrated the significant correlation between the satellite DNA methylation pattern varieties and chromosome aberration yields under various stress exposure modes. The role of satellite DNA methylation pattern variability and its changing in key responses to stress such as mobile elements’ activation, cell’s passage of checkpoints, and homological repair was discussed.
文摘目的:对T细胞淋巴瘤(T-cell lymphoma,TCL)6号染色体上6个微卫星多态标志物进行等位基因杂合性缺失(loss of heterozygosity,LOH)分析,以明确该区域是否存在与人类TCL发生发展相关的抑癌基因。方法:选取6号染色体上6个微卫星多态标志D6S251、D6S275、D6S287、D6S267、D6S262、D6S264,采用石蜡组织基因组DNA抽提、PCR扩增,变性聚丙烯酰胺凝胶垂直电泳、银染法分别检测了42例TCL中肿瘤组织与相应正常组织基因组DNA的LOH状况。结果:42例TCL中13例(13/42,30.95%)至少在1个位点出现LOH,以D6D262最高(10.3%),其次为D6S287(10.0%)和D6S267(7.3%)。而不同临床病理分型的TCL其LOH发生差异无统计学意义(P>0.05)。结论:在6号染色体上的6个微卫星标志中D6S287、D6S262和D6S267周围的6q21-6q23压域发生杂合性缺失率较高,位于6q21区编码Cyclin C的基因可能是此区与TCL发生发展相关的候选抑癌基因;尤其是6q21-6q22.1区域可能存在与TCL相关的抑癌基因,可能与TCL的发生发展有关。
