title: Global expression of cell surface proteins in embryonic stem cells.
abstract: BACKGROUND
  Recent studies have shown that embryonic stem (ES) cells globally express most genes in the genome at the mRNA level; however, it is unclear whether this global expression is propagated to the protein level. Cell surface proteins could perform critical functions in ES cells, so determining whether ES cells globally express cell surface proteins would have significant implications for ES cell biology.
  
  
  RESULTS
  The surface proteins of mouse ES cells were purified by biotin labeling and subjected to proteomics analysis. About 1000 transmembrane or secreted cell surface proteins were identified. These proteins covered a large variety if functional categories including signal transduction, adhesion and transporting. More over, mES cells promiscuously expressed a wide variety of tissue specific surface proteins. And many surface proteins were expressed heterogeneously on mES cells. We also find that human ES cells express a wide variety of tissue specific surface proteins.
  
  
  CONCLUSIONS
  Our results indicate that global gene expression is not simply a result of leaky gene expression, which could be attributed to the loose chromatin structure of ES cells; it is also propagated to the functional level. ES cells may use diverse surface proteins to receive signals from the diverse extracellular stimuli that initiate differentiation. Moreover, the promiscuous expression of tissue specific surface proteins illuminate new insights into the strategies of cell surface marker screening.
authors.affiliation: The Institute of Cell Biology and Genetics, College of Life Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Gu
authors.forename: Jiarong
authors.initials: J
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Lijuan
authors.initials: L
authors.lastname: Mo
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhou
authors.forename: Liangbiao
authors.initials: L
authors.lastname: Chen
authors.forename: Yusen
authors.initials: Y
authors.lastname: Liu
authors.forename: Ming
authors.initials: M
authors.lastname: Zhang
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002462:Cell Membrane / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism; D002853:Chromatography, Liquid / Q000379:methods; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism; D020869:Gene Expression Profiling / Q000379:methods*; D005786:Gene Expression Regulation; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods; D051379:Mice; D008813:Mice, Inbred ICR; D040901:Proteomics / Q000379:methods
chemical_list: D002843:Chromatin