[Heterochromatin regions of the chromosomes of the hen and Japanese quail in mitosis and at the lampbrush stage].
The mitotic and lampbrush chromosomes of the domestic fowl and Japanese quail were analysed by fluorochrome staining technique. The lampbrush chromosomes of both the subjects displayed a typical "loop-chromomere" structure. Three distinct kinds of loops were distinguished in Gallus g. domesticus--normal, telomeric bows, and lumps. The former are distributed along the whole chromosome length. The latter and the bows were observed in subtelomeric and telomeric regions. By DNA/RNA specific acridine orange staining it was shown that each loop (especially, "lumpy" loops) contained a rich RNP matrix. A comparative analysis of the chromomycin A3/distamycin A banding pattern of mitotic and lampbrush chromosomes shows that the telomeric "bows" and "lumps" are special loops developed in telomeric heterochromatic bands. In Coturnix c. japonica, the CMA/DA-positive bands were not observed in telomeres of mitotic macrochromosomes, except a smallest band in the 2p-arm telomere. The absence of telomeric heterochromatic bands which can be visualized in the quail mitotic chromosomes coincides with the absence of "bow"-like loops. Only small lump-like structures were seen in some telomeres of macroautosomes. The biological significance of loop formation and RNA synthesis in heterochromatic band loops in growing oocytes is briefly discussed.
Rodionov
A V
AV
Chelysheva
L A
LA
Kropotova
E V
EV
Gaginskaia
E R
ER
D000818:Animals; D002642:Chick Embryo; D002871:Chromosome Banding / Q000379:methods; D002875:Chromosomes / Q000648:ultrastructure*; D003370:Coturnix; D004247:DNA / Q000648:ultrastructure; D004625:Embryo, Nonmammalian / Q000648:ultrastructure; D005260:Female; D006570:Heterochromatin / Q000648:ultrastructure*; D008938:Mitosis; D012313:RNA / Q000648:ultrastructure
D006570:Heterochromatin; D012313:RNA; D004247:DNA
Geterokhromatinovye raĭony khromosom kuritsy i iaponskogo perepela v mitoze i na stadii lampovykh shchetok.