染色质
精子发生
鱼精蛋白
生物
前期
组蛋白
乌贼
细胞生物学
染色体早凝
染色质重塑
酸模
生物物理学
生物化学
DNA
官房
核心
植物
减数分裂
基因
肝素
作者
Fina Martínez‐Soler,Kathryn Kurtz,Juan Ausió,Manel Chiva
摘要
During spermiogenesis of Sepia officinalis histones are directly substituted by a molecule of precursor protamine, which is later transformed into the protamine through a deletion of the amino terminal end. In the present work, it is shown that the pattern of spermiogenic chromatin condensation consists of a phase of "patterning" and a phase of "condensation." In the phase of patterning, three structural remodelings are produced in the chromatin structure: [somatic-like chromatin --> 18 nm granules --> 25 nm fibers --> 44 nm fibers]. The first remodeling of the chromatin into granules of 18 nm takes place without the entrance of specific proteins in the spermiogenic nuclei. The second remodeling [granules of 18 nm --> fibers of 25 nm] is due to the entrance of the precursor protamine and its interaction with the DNA-histone complex. The third remodeling [fibers of 25 nm --> fibers of 44 nm] occurs simultaneously with the disappearance of histones from the chromatin. In the phase of condensation, the fibers of 44 nm coalesce among themselves to form progressively larger aggregates of chromatin. In this phase there are no substantial variations in the nuclear proteins, so that the condensation of the chromatin must respond to posttranscriptional changes of the precursor protamine (dephosphorylation, deletion of the amino-terminal end).
科研通智能强力驱动
Strongly Powered by AbleSci AI