弗吉尼亞的生物技術專家和工程學專家建立了一套數(shù)學模型,，根據(jù)這一模型,，研究者可以觀察細胞在分裂周期中處理信息的模式，其中有多少分子會參與其中,。這一有趣的成果發(fā)表在最新一期的《美國科學院院報》（PNAS）上,。
參與研究的有博士后Sandip Kar，電子計算機工程學教授William Baumann,，工程機制研究教授,，著名的生物科學教授John Tyson。
研究小組以單個酵母細胞為模型，研究細胞的信息流,，輸入的信息流和輸出的信息流,，細胞中mRNA的流向和功效。
研究結果表明,，在細胞分裂周期中平均參與的mRNA數(shù)是正常狀態(tài)下的5-10倍,；mRNA分子的半衰期比正常狀態(tài)下短10-20倍,；在細胞中,，有50%的蛋白傳遞的信息是雜音,，因此細胞必然有套獨特的消除背景本底的系統(tǒng)以便清除一些無用的信息,。研究發(fā)現(xiàn)在細胞中每個基因?qū)粋€mRNA分子，每個mRNA分子只有15-20分鐘的存活時間,，之后便降解,。（生物谷Bioon.com）
生物谷推薦原始出處：
PNAS February 25, 2009, doi: 10.1073/pnas.0810034106
Exploring the roles of noise in the eukaryotic cell cycle
Sandip Kara, William T. Baumannb, Mark R. Paulc and John J. Tysona,1
aDepartments of aBiological Sciences,
bElectrical and Computer Engineering, and
cMechanical EngineeringVirginia Polytechnic Institute and State UniversityBlacksburg, VA 24061
Edited by John RossStanford UniversityStanfordCA approved January 11, 2009 (received for review December 30, 2008)
Abstract
The DNA replication–division cycle of eukaryotic cells is controlled by a complex network of regulatory proteins, called cyclin-dependent kinases, and their activators and inhibitors. Although comprehensive and accurate deterministic models of the control system are available for yeast cells, reliable stochastic simulations have not been carried out because the full reaction network has yet to be expressed in terms of elementary reaction steps. As a first step in this direction, we present a simplified version of the control system that is suitable for exact stochastic simulation of intrinsic noise caused by molecular fluctuations and extrinsic noise because of unequal division. The model is consistent with many characteristic features of noisy cell cycle progression in yeast populations, including the observation that mRNAs are present in very low abundance (≈1 mRNA molecule per cell for each expressed gene). For the control system to operate reliably at such low mRNA levels, some specific mRNAs in our model must have very short half-lives (<1 min). If these mRNA molecules are longer-lived (perhaps 2 min), then the intrinsic noise in our simulations is too large, and there must be some additional noise suppression mechanisms at work in cells.
