|Freking, Bradley - Brad|
Submitted to: Journal of Molecular Endocrinology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/11/2013
Publication Date: 8/1/2013
Publication URL: http://handle.nal.usda.gov/10113/59670
Citation: Schennink, A., Trott, J.F., Freking, B.A., Hovey, R.C. 2013. A novel first exon directs hormone-sensitive transcription of the pig prolactin receptor. Journal of Molecular Endocrinology. 51(1):1-13. Interpretive Summary: Improving sow lactation performance using management tools or different nutritional strategies is of current relevance to the swine industry. Inadequate milk production can impair survival rates and the pre- and post-weaning growth of piglets so there is a need for a better understanding of the hormonal regulation of milk production. The polypeptide hormone prolactin (PRL) regulates numerous physiological functions across multiple species through the PRL receptor (PRLR). The most pronounced effects of PRL in pigs are its role in growth of the udder and milk production and in reproduction, but it also influences stress responses and behavior of the sow. This diversity of responses to PRL highlights the important role for the PRLR and its regulation. Results of this study indicated that the gene for PRLR is regulated differently in different tissues and by different hormones. This diversity in control of the gene could be crucial to the many biological functions of PRL, where this information contributes to a better understanding of milk production in the pig.
Technical Abstract: Endocrine, paracrine, and autocrine prolactin (PRL) acts through its receptor (PRLR) to confer a wide range of biological functions, including its established role during lactation.We have identified a novel first exon of the porcine PRLR that gives rise to three different mRNA transcripts. Transcription of this first exon is tissue specific, where it increases during gestation in the adrenal glands and uterus. Within the mammary glands, its transcription is induced by estrogen and PRL, while in the uterus, its expression is downregulated by progestin. The promoter region has an enhancer element located between -453 and -424 bp and a putative repressor element between -648 and -596 bp. Estrogen, acting through the estrogen receptor, activates transcription from this promoter through both E-box and transcription factor AP-2 alpha binding sites. These findings support the concept that the multilevel hormonal regulation of PRLR transcription contributes to the various biological functions of PRL.