Studies On The Relationship Between Polymorphism Of Porcine POU1F1 Gene And The MRNA Express Of Interrelated Gene

POU1F1 (pituitary transcription factor 1) is a member of the POU-domain families. It acts as a positive regulatory factor of GH, PRL and TSH- β genes, and plays the important role in the normal development and growth of mammals. So POU1F1 was considered to play a very important role in growth and carcass traits of porcine. Therefore, it is selected as a candidate gene for growth trait.In this study, a partial region polymorphisms of porcine POU1F1 of four breeds: Yorkshare, Zhongxu black, Xiang and Hebao (Min) , were investigated. Based on the results of PCR-SSCP and PCR-RFLP, four mutation sites was selected and the relationship between polymorphisms and growth traits was analyzed. In the same time, mRNA expressions of POUIF1, GH, PRL and TSH- β was mensurated by RQ-PCR. The association of DNA polymorphisms and mRNA expressions was construed.Four polymorphisms had been identified.The association of growth traits and genotypes was analyzed. Distrbution of corresponding genotypes in exon 4 was analyzed as well. We found the genotype distribution of exon 4 (273bp) was quite different in four breeds.The genotype AA often appeared in Yorkshare and Zhongxu Black, while genotype BB was present in Xiang. The polymorphism of exon 4 (273bp) significantly associatiated with backfat thickness(R=0.499, P<0.05) in Zhongxu black.RsaI-RFLP and PstI-RFLP polymorphisms of the region 1747bp (between intron 4 and exon 6) were validated. The RsaI-RFLP genotype of this region was mostly AA in four breeds.The correlation analysis showed the significant association between daily weight gain before ablactation and RsaI-RFLP genotype in Hebao, and the allele B could increase the POU1F1 mRNA expression (R=-0.449, P<0.05). PstI-RFLP polymorphism showed a significant association with the P0U1F1 and PRL mRNA expressions (P<0.01) in Yorkshare, but no relationship was discovered in growth traits.A SNP of T→ C in intron 1 (1515bp), marked correlated with the daily live weight gain after ablactation (P<0.05) and the expression of GH (P<0.05). So the SNP may play an important role in the GH expression and affect daily weight gain by controling of GH. After analysing the correlation of mRNA expressions in P0U1F1, GH, PRL and TSH-β, we arrive in conclusion: POU1F1 regulated GH, PRL, TSH-β expressions by mRNA expression level.The results as follows:1. An identified mutation of exon 4 (C→ T) would decrease backfat thickness in Zhong xu black pigs.2. The RsaI-RFLP polymorphism of the region of 1747bp (between intron 4 and exton 6 ) may increase P0U1F1 expression and early daily weight gain.3. A PstI-RFLP polymorphism of the region of 1747bp between intron 4 and exton 6 may decrease POU1F1 and PRL expression.4. A new mutation site of intron 1, T→ C translation, was detected. The mutation maybe affects the GH expression and decreases the later daily weight gain.5. mRNA expression level of POU1F1 affects the function to GH, PRL,TSH-β.