Cloning and functional characterization of allelic variation in the porcine prolactin receptor

Abstract 

Prolactin (PRL) regulates various functions in pigs including reproduction, mammary development and lactation. We used 5′-rapid amplification of cDNA ends (5′-RACE) to clone three full-length alleles of the porcine PRL receptor (pPRLR) from Landrace (alleles LR2 and LR4) and Yucatan miniature (MP) pigs, corresponding to the A and B alleles previously reported to be associated with reproductive traits. When expressed in Chinese hamster ovary (CHO-K1) cells, all three pPRLRs transduced differentiation signals to a β-casein promoter with the same effectiveness, where human growth hormone (hGH) and porcine PRL (pPRL) were more effective ligands than ovine PRL (oPRL). The pPRLR had a lower binding affinity for oPRL than pPRL while binding affinity for hGH was not different between the three pPRLR variants. The pPRLRs primarily localized to the cytoplasm with perinuclear concentration. In conclusion, we have cloned three allelic variants of the pPRLR and have functionally characterized these as different from the hPRLR. However, our data do not support the proposal that allelic variation of the pPRLR confers functional differences in vivo.

Abbreviations: AMV-RT, avian myeloblastosis virus reverse transcriptase, CHO-K1, Chinese hamster ovary K1 cells, ECD, extracellular domain, EF, elongation factor-α1, h, human, hGH, human growth hormone, HRP, horseradish peroxidase, LPG-A, lysosomal membrane glyocoprotein-A, LR, Landrace, MMLV-RT, Moloney murine leukemia virus reverse transcriptase, MP, miniature pig, o, ovine, p, porcine, PRL, prolactin, PRLR, prolactin receptor, RACE, rapid amplification of cDNA ends

Keywords: Reproduction, Prolactin receptor, Tissue distribution, Polymorphism, Porcine