Study On The Expression Characteristics And Genetic Effects Of MMP-13 Gene In Chicken

During chicken follicle growth, extracelluar matrix(ECM) undergoes remodeling continuously, cell-cell and cell-matrix interactions coordinated by matrix metalloproteinases(MMPs) and their associated endogenous inhibitors(TIMPs). MMP-13 is reported to degrade interstitial collagens, type IV and type IX collagens and various ECM components. In this study, the role of MMP-13 in chicken follicle development and its relationship with egg production traits were analyzed. The results were as follows:1. The results of RT-PCR and Western blotting showed that the expression of the MMP-13 in sexual immaturity chicken ovary was lower that of sexually mature hens. In different follicles, the expression of MMP-13 mRNA increased from SW(the small white follicle) to F5(the fifth large follicle), then decreased to F1(the first large follicle) and dramatically increased again in POF1(the first post-ovulatory follicle)(P<0.05). The expression trend of MMP-13 protein was identical with that of mRNA, but the difference was not significant(P>0.05).2. The immunohistochemistry results showed that MMP-13 protein was detected in membrane cells, oocytes, stromal cells and granulosa cells of of sexually immature chicken(45d) ovary. MMP-13 protein was localized in membrane layer of sexually mature chicken ovaries and distributed in peripheral vascular.3. Furthermore, we identified positive element(–1863 to –1036 sites) controlling chicken MMP-13 transcription, and in this region, six SNPs were found and genotyped in chicken populations. In White Recessive Rock population, hens with A–1356-C–1079/A–1356-C–1079 genotype had earlier age at first laying than those with the G–1356-T–1079/G–1356-T–1079 genotype(P<0.05).4. Finally, we found the activity of A–1356-C–1079 genotype was lower than that of G–1356-T–1079 genotype by constructing differe gene vector and luciferase assay(P<0.01). And the analysis results of bioinformatics online software(http://www.genomatix.de/index.html) showed that binding sites of MELS, KLF7 and Grhl2 transcription factor was at-1356,-1128 and-1094 loci respectively.These results collectively suggest that MMP-13 plays an important role in chicken follicle growth and POF regression and polymorphisms in its promoter region could be used as molecular markers for improving age at first laying trait in chicken breeding.