Volff J N, Altenbuchner J
Physiologische Chemie I, Biozentrum der Universität Würzburg, Germany.
Mol Microbiol. 1998 Jan;27(2):239-46. doi: 10.1046/j.1365-2958.1998.00652.x.
The Streptomyces wild-type chromosome is linear in all examples studied. The ends of the chromosome or telomeres consist of terminal inverted repeats of various sizes with proteins covalently bound to their 5' ends. The chromosome is very unstable and undergoes very large deletions spontaneously at rates higher than 0.1% of spores. Frequently, the telomeres are included in the deletions. Loss of both telomeres leads to circularization of the chromosome. The wild-type chromosome can also be circularized artificially by targeted recombination. Spontaneously or artificially circularized chromosomes are even more unstable than the linear ones. High-copy-number tandem amplifications of specific chromosomal regions are frequently associated with the deletions. RecA seems to be involved in the amplification mechanism and control of genetic instability.
在所研究的所有实例中，链霉菌野生型染色体是线性的。染色体末端或端粒由各种大小的末端反向重复序列组成，蛋白质共价结合在其5'末端。染色体非常不稳定，会以高于0.1%的孢子率自发地发生非常大的缺失。端粒经常包含在缺失中。两个端粒的缺失会导致染色体环化。野生型染色体也可以通过靶向重组人工环化。自发或人工环化的染色体比线性染色体更不稳定。特定染色体区域的高拷贝数串联扩增经常与缺失相关。RecA似乎参与了扩增机制和遗传不稳定性的控制。
