主页 > 生命科学 >
【bio-news】Single-cell proteomic analysis
changes in their concentrations can have direct phenotypic
consequences. Several approaches have been used to identify
proteins expressed in a diverse range of organisms and organelles1–4.
In particular, studies on the budding yeast Saccharomyces cerevisiae
have generated a nearly comprehensive list of proteins likely to be
translated5–7 and their copy numbers at steady state in rich medium6.
However, much less quantitative information is available on how
proteomes are remodelled in response to different environmental
cues. Additionally, inferences about changes in protein levels based
on DNA microarray measurements are limited by an imperfect
understanding of the relationship between mRNA and protein
levels6,8–10.
Notably, no widely used proteomics technique readily provides
abundance measurements for single cells, although such information
is critical for understanding fundamental biological questions.
Indeed, it has long been appreciated that many cellular processes
rely on small numbers of molecules and thus are subject to stochastic
variation (noise)11. Such noise contributes to phenotypic variability
and can either attenuate or augment a cell’s ability to respond to its
environment12–14. Even in the absence of noise, epigenetic imprints15
and a lack of synchronicity within a population can differentially
impact transcription from genetically identical loci. Also, protein
changes can occur in both graded and binary (switch-like) fashions in
response to differing environmental conditions, but bulk measurements
obscure such responses16–18. Thus, identifying single-cell variation
is essential for understanding how cells exist as autonomously
functioning dynamic systems19.
Pioneering studies have highlighted the potential of flow cytometry
to quantify intracellular protein concentrations in individual cells20,
and to measure different samples rapidly21. More recently, several
elegant studies using the green fluorescent protein (GFP) and its
derivatives have identified many factors that can contribute to
noise15,22–25. However, the scope and nature of the central factors
that give rise to and limit noise in vivo remain poorly understood (see
ref. 26), in large part because existing studies have examined only a
handful of genes.
Here we describe a novel, integrated strategy for large-scale,
quantitative single-cell proteomics. Our approach uses highthroughput
flow cytometry to make precise measurements on a
collection of S. cerevisiae strains in which each protein is expressed as
a carboxy-terminal GFP fusion from its endogenous promoter and
natural chromosomal position3. With this approach, it is now
possible to monitor the internal state of the cell with unprecedented
resolution. This allows us to follow protein changes in response to
environmental perturbations and to uncover both the global and
protein-specific biological structure of noise in budding yeast. 本人认领这篇，48小时未交稿，其他战友自由认领 没时间看，放弃了，抱歉！ [标签:content1][标签:content2]
阅读本文的人还阅读：
作者:admin@医学,生命科学 2011-06-01 14:42
医学,生命科学网