芽殖酵母是衰老研究的一個(gè)重要模型,。細(xì)胞通過(guò)在母細(xì)胞表面上一個(gè)芽的形成而發(fā)生非對(duì)稱分裂,，母細(xì)胞經(jīng)過(guò)幾代之后就會(huì)衰老,，因此其壽命是有限的。芽殖酵母物種的延續(xù)取決于這樣一個(gè)事實(shí)：它的芽每次生出時(shí)都是“年輕”的,。衰老因子,，如羰化蛋白和DNA環(huán),，已知仍然約束于母細(xì)胞，因而可將芽的年齡重設(shè)為零,，但科學(xué)家對(duì)這種約束的機(jī)制卻很不了解?，F(xiàn)在，Shcheprova等人發(fā)現(xiàn),，在正在發(fā)生分裂的酵母核的核被膜中,，會(huì)形成一個(gè)擴(kuò)散障礙。這個(gè)障礙阻止先前存在的核孔和其他與膜相關(guān)的蛋白進(jìn)入芽中,。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature 454, 728-734 (7 August 2008) | doi:10.1038/nature07212
A mechanism for asymmetric segregation of age during yeast budding
Zhanna Shcheprova1, Sandro Baldi1, Stephanie Buvelot Frei1, Gaston Gonnet2 & Yves Barral1
Institute of Biochemistry, Biology Department, ETH Zurich, Schafmattstrasse 18, 8093 Zurich, Switzerland
Institute of Computational Science, Department of Computer Science, ETH Zurich, Universtätstrasse 6, 8092 Zürich, Switzerland
Correspondence to: Yves Barral1 Correspondence and requests for materials should be addressed to Y.B. (Email: [email protected]).
Abstract
Ageing and the mortality that ensues are sustainable for the species only if age is reset in newborns. In budding yeast, buds are made young whereas ageing factors, such as carbonylated proteins and DNA circles, remain confined to the ageing mother cell. The mechanisms of this confinement and their relevance are poorly understood. Here we show that a septin-dependent, lateral diffusion barrier forms in the nuclear envelope and limits the translocation of pre-existing nuclear pores into the bud. The retention of DNA circles within the mother cell depends on the presence of the diffusion barrier and on the anchorage of the circles to pores mediated by the nuclear basket. In accordance with the diffusion barrier ensuring the asymmetric segregation of nuclear age-determinants, the barrier mutant bud6 fails to properly reset age in buds. Our data involve septin-dependent diffusion barriers in the confinement of ageing factors to one daughter cell during asymmetric cell division.bioon
