Murphy T D, Karpen G H
Molecular Biology and Virology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037, USA.
Cell. 1995 Aug 25;82(4):599-609. doi: 10.1016/0092-8674(95)90032-2.
The DNA elements responsible for centromere activity in a metazoan have been localized using the Drosophila minichromosome Dp1187. Deleted minichromosomes were generated by irradiation mutagenesis, and their molecular structures were determined by pulsed-field Southern blot analysis. Analyses of the transmission behavior of Dp1187 derivatives localized sequences necessary for chromosome inheritance within the centric heterochromatin. The essential core of the centromere is contained within a 220 kb region that includes significant amounts of complex DNA. Completely normal inheritance also requires approximately 200 kb on either side of the essential core. This flanking DNA predominantly contains highly repeated sequences, and the amount required for normal transmission differs among division types and between the sexes. We propose that the essential core is the site of kinetochore formation and that flanking DNA provides two functions: sister chromatid cohesion and indirect assistance in kinetochore formation or function.
利用果蝇微小染色体Dp1187，已确定了后生动物中负责着丝粒活性的DNA元件的位置。通过辐射诱变产生缺失的微小染色体，并通过脉冲场Southern印迹分析确定其分子结构。对Dp1187衍生物的传递行为分析，将染色体遗传所需的序列定位在着丝粒异染色质内。着丝粒的基本核心包含在一个220 kb的区域内，该区域包含大量复杂DNA。完全正常的遗传在基本核心两侧还需要大约200 kb。这种侧翼DNA主要包含高度重复序列，正常传递所需的量在不同分裂类型和两性之间有所不同。我们提出，基本核心是动粒形成的位点，侧翼DNA提供两种功能：姐妹染色单体黏连以及对动粒形成或功能的间接辅助。
