IN the late 1970s, biochemical analysis and electron microscopy of isolated, histone-depleted mitotic chromosomes demonstrated the existence of a central scaffold consisting mainly of nonhistone proteins (NHPs) in met...IN the late 1970s, biochemical analysis and electron microscopy of isolated, histone-depleted mitotic chromosomes demonstrated the existence of a central scaffold consisting mainly of nonhistone proteins (NHPs) in metaphase chromosomes. Subsequently, by using silver impregnation techniques and light microscopy, Howell et al. showed the presence of an axial chromatid core in relatively intact chromosomes of mammals; this core is believed to be展开更多
An argentophilic structure is present in the metaphase chromosomes of garlic (Allium sativum). Cytochemical studies indicate that the main component of the structure is non-histone proteins (NHPs). The results of ligh...An argentophilic structure is present in the metaphase chromosomes of garlic (Allium sativum). Cytochemical studies indicate that the main component of the structure is non-histone proteins (NHPs). The results of light and electron microscopic observations reveal that the chromosme NHP scaffold is a network which is composed of fibres and granules and distributed throughout the chromosomes. In the NHP network, there are many condensed regions that are connected by relatively looser regions. The distribution of the condensed regions varies in individual chromosomes. In some of the chromosomes the condensed regions are longitudinally situated in the central part of a chromatid while in others these regions appear as coillike transverse bands. At early metaphase, scaffolds of the sister chromatids of a chromosome are linked to each other in the centromeric region, meanwhile, they are connected by scafold materials along the whole length of the chromosome. At late metaphase, however, the connective scaffold materials between the two sister chromatids disappear gradually and the chromatids begin to separate from one another at their ends, but the Chromatids are linked.together in the centromeric region until anaphase. This connection seems to be related to the special structure of the NHP scaffold formed in the centromeric region. The morphological features and dynamic changes of the chromosome scaffold are discussed.展开更多
文摘IN the late 1970s, biochemical analysis and electron microscopy of isolated, histone-depleted mitotic chromosomes demonstrated the existence of a central scaffold consisting mainly of nonhistone proteins (NHPs) in metaphase chromosomes. Subsequently, by using silver impregnation techniques and light microscopy, Howell et al. showed the presence of an axial chromatid core in relatively intact chromosomes of mammals; this core is believed to be
文摘An argentophilic structure is present in the metaphase chromosomes of garlic (Allium sativum). Cytochemical studies indicate that the main component of the structure is non-histone proteins (NHPs). The results of light and electron microscopic observations reveal that the chromosme NHP scaffold is a network which is composed of fibres and granules and distributed throughout the chromosomes. In the NHP network, there are many condensed regions that are connected by relatively looser regions. The distribution of the condensed regions varies in individual chromosomes. In some of the chromosomes the condensed regions are longitudinally situated in the central part of a chromatid while in others these regions appear as coillike transverse bands. At early metaphase, scaffolds of the sister chromatids of a chromosome are linked to each other in the centromeric region, meanwhile, they are connected by scafold materials along the whole length of the chromosome. At late metaphase, however, the connective scaffold materials between the two sister chromatids disappear gradually and the chromatids begin to separate from one another at their ends, but the Chromatids are linked.together in the centromeric region until anaphase. This connection seems to be related to the special structure of the NHP scaffold formed in the centromeric region. The morphological features and dynamic changes of the chromosome scaffold are discussed.
