Human Epididymis Proteomics - The Establishment Of Technology Platforms And Bioinformatics Analysis

The epididymis is a key structure of the male reproductive system, its function is tomature, transport and store sperm. The epididymis is grossly divided into four majorregions: initial segment,caput, corpus and cauda. The spermatogenesis events in the testisare under the genomic regulation of the gamete,and DNA begins to condense in theelongated spermatids,but their motility and the ability to recognize and to fuse with theoocyte is gained only after a transit through the epididymis during which the spermatozoafrom the testis travel to the vas deferent.Many scientists have focued on the study of thestructure,gene and protein expression of epididymis since 1960, but due to the difficulty ofsample source,most study focused on the animal model,and little attention has been given tohuman epididymis.Proteome analysis of human epididymal fluid and tissue proteome willprovid valuable information about the male reproductive system and provid abundantindications for further research in this field.Rat epididymal fluid proteins was the first study subject, the epididymal fluid proteinsextracted were exchanged with start buffer and separated by chromatofocusing in the firstdimension,the fractions between pH8.5 and pH4.0 collected from 1D were separated byreverse-phase HPLC,the fractions were collected by automatic fraction collector;The UVmaps were transformed into PI/UV maps by ProteoVue software;The fractions includinghigh abundance proteins were identified using MALDI-TOF MS(ERABP, Clusterin,CRISP).Human epididymal fluid proteins and tissue proteins were extracted through the aboveexperience,and separated by PF2D and 2D,respectively.The 2D expression graph wereanalyzed through Imagemaster,and the spot numbers of fluid proteins and tissue proteins were265±23(F_caput), 207±32(F_corpus), 234±25(F_cauda); 1092±30(T_caput), 1002±42(T_corpus), 987±23(T_cauda).All visible spot were extracted and identificated by MALDI-TOFMASS,145 and 415 nonredundance proteins were identificated,which represented 405 and1720 identificated proteins.This phenomenon indicted the polymorphism of PI and MW ofepidydymal proteins. All the protein datum were interpreted and classified by bioinformatics tools include GO, KEGG,Biocarta and VisANT, etc. According to the annotation ofGeneOntology, 112 of 145 fluid proteins have molecular functions and 94 proteins participatein the biology process, 376 of 415 tissue proteins have molecular functions and 345 proteinsparticipate in the biology process. Glycolysis is one of the main pathways of epididyamlproteins.Through Integration of bioinformatics analysis can found that epididymal fluidproteins may participate in the composition and changes in the sperm membrane or cancontribute to the preservation of sperm integrity,epididymal tissue proteins which contain manymetabolic enzymes andstructural proteins may have the physiological functions,and caput mayhave more activity than other segments.