Holló G, Keresö J, Praznovszky T, Cserpán I, Fodor K, Katona R, Csonka E, Fátyol K, Szeles A, Szalay A A, Hadlaczky G
Institute of Genetics, Hungarian Academy of Sciences, Szeged, Hungary.
Chromosome Res. 1996 Apr;4(3):240-7. doi: 10.1007/BF02254965.
We have analysed the replication of the heterochromatic megachromosome that was formed de novo by a large-scale amplification process initiated in the centromeric region of mouse chromosome 7. The megachromosome is organized into amplicons approximately 30 Mb in size, and each amplicon consists of two large inverted repeats delimited by a primary replication initiation site. Our results suggest that these segments represent a higher order replication unit (megareplicon) of the centromeric region of mouse chromosomes. Analysis of the replication of the megareplicons indicates that the pericentric heterochromatin and the centromere of mouse chromosomes begin to replicate early, and that their replication continues through approximately three-quarters of the S-phase. We suggest that a replication-directed mechanism may account for the initiation of large-scale amplification in the centromeric regions of mouse chromosomes, and may also explain the formation of new, stable chromosome segments and chromosomes.
我们分析了通过在小鼠7号染色体着丝粒区域启动的大规模扩增过程而从头形成的异染色质巨染色体的复制情况。该巨染色体由大小约为30 Mb的扩增子组成，每个扩增子由两个由主要复制起始位点界定的大型反向重复序列组成。我们的结果表明，这些片段代表了小鼠染色体着丝粒区域的一个高阶复制单元（巨复制子）。对巨复制子复制的分析表明，小鼠染色体的着丝粒周围异染色质和着丝粒在早期开始复制，并且它们的复制持续约四分之三个S期。我们认为，一种复制导向机制可能解释了小鼠染色体着丝粒区域大规模扩增的起始，也可能解释了新的、稳定的染色体片段和染色体的形成。
