title: Systematic analysis of gene expression level with tissue-specificity, function and protein subcellular localization in human transcriptome.
abstract: Recent studies have shown that, in mammals, the highly expressed genes have shorter gene length and their protein products have relatively lower evolutionary rates. However, the global relationship between genes' expression level and their features such as tissue-specificity, function and protein subcellular localization has not been investigated extensively, especially in mammalian. In order to solve it, we analysed 8,570 genes across 46 human tissues. Our results suggest that widely expressed genes have higher mean expression levels than tissue-specific ones and genes encoding zinc-finger proteins have low expression levels similar to that of DNA-binding proteins. In the analysis of protein subcellular localization, it is shown that nuclear and Golgi apparatus proteins have lower mean expression levels than those of mitochondria, endoplasmic reticulum and membrane proteins, while genes encoding cytoplasm and extracellular components display the highest expression levels. When comparing the gene expression levels and the number of expressed genes in different tissues, we found that some tissues have less active genes while single gene encodes relatively more transcripts. Taken together, gene expression levels are clearly correlated with their tissue-specificity, function and protein subcellular localization, and are highly conserved during evolution.
authors.affiliation: State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, 220 Handan Road, Shanghai, 200433, People's Republic of China. lq054@hotmail.com
authors.forename: Qiang
authors.initials: Q
authors.lastname: Li
authors.forename: Xianghua
authors.initials: X
authors.lastname: Liu
authors.forename: Quanyuan
authors.initials: Q
authors.lastname: He
authors.forename: Lei
authors.initials: L
authors.lastname: Hu
authors.forename: Yichen
authors.initials: Y
authors.lastname: Ling
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Wu
authors.forename: Xianmei
authors.initials: X
authors.lastname: Yang
authors.forename: Long
authors.initials: L
authors.lastname: Yu
mesh_terms: D002462:Cell Membrane / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D019143:Evolution, Molecular; D005109:Extracellular Matrix / Q000378:metabolism; D015870:Gene Expression; D020869:Gene Expression Profiling / Q000379:methods*; D005796:Genes / Q000235:genetics; D006801:Humans; D009928:Organ Specificity / Q000235:genetics*; D015388:Organelles / Q000378:metabolism; D011506:Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D011506:Proteins