拟核，一种能够进行链延伸的亚核系统。

Nucleoids, a subnuclear system capable of chain elongation.

作者信息

Collins J M, Wood S H, Chu A K

机构信息

Department of Biochemistry and Molecular Biophysics, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond.

出版信息

Biochim Biophys Acta. 1989 Dec 22;1009(3):264-76. doi: 10.1016/0167-4781(89)90112-7.

DOI:10.1016/0167-4781(89)90112-7

PMID:2597677

Abstract

Nucleoids, prepared by salt extraction of non-DNase-digested nuclei, have properties similar, but not identical, to those of nuclear matrices which are prepared by salt extraction of DNase-digested nuclei. Nuclear matrices retained less pulse-labelled DNA, slightly less bound DNA polymerase alpha and DNA primase, but had greater in vitro DNA synthesis and in vitro priming. Nucleoids contained larger (110 S) DNA chains than nuclear matrices (30 S). Each type of residual nuclear structure could synthesize 4.5 S Okazaki fragments. When extracted with increasing concentrations of salt, DNase-digested nucleo lost the ability for further elongation of the 4.5 S DNA intermediate after 0.1-0.2 M NaCl, whereas undigested nuclei retained this ability up to 0.9 M NaCl. Chain elongation to 28 S DNA chains could be restored to nucleoids, but not to nuclear matrices, by the addition of nuclear extracts.

摘要

通过对未用DNA酶消化的细胞核进行盐提取制备的类核，其性质与通过对用DNA酶消化的细胞核进行盐提取制备的核基质相似，但不完全相同。核基质保留的脉冲标记DNA较少，结合的DNA聚合酶α和DNA引发酶略少，但具有更强的体外DNA合成能力和体外引发能力。类核所含的DNA链（110 S）比核基质（30 S）更大。每种类型的残余核结构都能合成4.5 S冈崎片段。用浓度不断增加的盐进行提取时，用DNA酶消化的类核在0.1 - 0.2 M NaCl后失去了进一步延长4.5 S DNA中间体的能力，而未消化的细胞核在高达0.9 M NaCl时仍保留这种能力。通过添加核提取物，类核可恢复到28 S DNA链的链延长能力，但核基质不能。