title: Proteomic profiling of regionalized proteins in rat epididymis indicates consistency between specialized distribution and protein functions.
abstract: The epididymis is a key structure of the male reproductive system; its function is to mature, transport, and store sperm. Most of the research examining the epididymis to date has been limited to the study of the secreted proteins involved in the maturation of spermatozoa. However, it is also very important to understand the protein components, regulation and function of the tissue itself since these are the basis for all of its physiological processes. We investigated the differential expression of proteins among the caput, corpus, and cauda regions of rat epididymis and considered the possible links between the localization of these proteins and the different functions of these epididymal regions. High-resolution 2-D gel electrophoresis followed by mass spectrometry (MS) revealed 28 distinct proteins whose expression levels varied from the caput to the cauda epididymis. Sixteen of them were reported for first time to be expressed in the epididymis. Expression patterns of some proteins were validated by Northern blot or Western blot. Immunohistochemistry revealed that inducible carbonyl reductase (iCR), an important enzyme in the anti-oxidative system, exhibits primary and cell-type specific distribution in the distal cauda region. Moreover, analysis of iCR transcription in castrated animals showed that its expression is androgen-dependent. Together with its known functions, iCR may also be involved in androgen metabolism and maintaining a steady microenvironment in the duct of epididymis.
authors.affiliation: Key Laboratory of Proteomics, Graduate School of the Chinese Academy of Sciences, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, Peoples Republic of China.
authors.forename: Haixin
authors.initials: H
authors.lastname: Yuan
authors.forename: Aihua
authors.initials: A
authors.lastname: Liu
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Hu
authors.initials: H
authors.lastname: Zhou
authors.forename: Yiguo
authors.initials: Y
authors.lastname: Wang
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.forename: Guoquan
authors.initials: G
authors.lastname: Wang
authors.forename: Rong
authors.initials: R
authors.lastname: Zeng
authors.forename: Yonglian
authors.initials: Y
authors.lastname: Zhang
authors.forename: Zhengjun
authors.initials: Z
authors.lastname: Chen
mesh_terms: D000429:Alcohol Oxidoreductases / Q000378:metabolism; D000728:Androgens / Q000502:physiology; D000818:Animals; D015180:Electrophoresis, Gel, Two-Dimensional; D004822:Epididymis / Q000378:metabolism*; D037502:Galectin 3 / Q000378:metabolism; D005786:Gene Expression Regulation; D008297:Male; D009919:Orchiectomy; D020543:Proteome / Q000032:analysis*; D051381:Rats; D017208:Rats, Wistar; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000728:Androgens; D037502:Galectin 3; D020543:Proteome; D000429:Alcohol Oxidoreductases