Sequence of DNA replication in Allium fistulosum chromosomes during S-phase.
Bromodeoxyuridine pulse labelling and immunodetection were applied to synchronized Allium fistulosum cells to study sequential changes in the chromosome replication pattern during S-phase. The replication patterns were classified into five main types depending on the location of the replication signals: (1) over the whole chromosomes; (2) at proximal and interstitial regions; (3) at proximal, interstitial and distal regions; (4) at interstitial and distal regions; and (5) at distal regions. The frequencies of each pattern changed sequentially according to the timing of BrdU incorporation, demonstrating the temporal order of chromosome replication during S-phase. The distal regions that correspond to the major C-bands replicated throughout S-phase except for the earliest stage, but most intensely in late S-phase. The replication time of different chromosome sites overlapped, which is quite different from the biphasic mode of replication that occurs in mammalian chromosomes.
Fujishige
I
I
Laboratory of Plant Chromosome and Gene Stock, Faculty of Science, Hiroshima University, Japan.
Taniguchi
K
K
D000490:Allium / Q000235:genetics* / Q000254:growth & development; D001973:Bromodeoxyuridine / Q000378:metabolism; D002871:Chromosome Banding; D002875:Chromosomes / Q000378:metabolism* / Q000648:ultrastructure; D004261:DNA Replication; D016196:S Phase
D001973:Bromodeoxyuridine