Submitted to: Biology of Reproduction
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/28/2002
Publication Date: 3/1/2003
Citation: KIM, J.G., SONG, J.H., VALLET, J.L., ROHRER, G.A., JOHNSON, G.A., JOYCE, M.M., CHRISTENSON, R.K. MOLECULAR CHARACTERIZATION AND EXPRESSION OF PORCINE BONE MORPHOGENETIC PROTEIN RECEPTOR-IB IN THE UTERUS OF CYCLIC AND PREGNANT GILTS. BIOLOGY OF REPRODUCTION. 2003. v. 68(3). p. 735-743.
Interpretive Summary: Recently, it was reported that single nucleotide mutation in the bone morphogenetic protein receptor-IB (BMPR-IB) gene was associated with increased ovulation rate in the Booroola Merino breed of sheep. Interestingly, comparison of the porcine genetic map with the more detailed human genetic map suggested that the porcine BMPR-IB gene may be located in a region on porcine chromosome 8 that is associated with increased uterine capacity and litter size in swine. We cloned the full coding region for BMPR-IB gene (3559 base pair). In cyclic White composite gilts, uterine BMPR-IB gene expression was increased on Day 13 and 15, as compared to Day 10. Expression of BMPR-IB gene was localized to the inner uterine lining, including both luminal and glandular epithelial cells on Day 15. However, BMPR-IB gene expression was less responsive in pregnant gilts. The location of the BMPR-IB gene was identified on swine chromosome 8. These findings show that BMPR-IB gene expression is temporally up-regulated during the estrous cycle. The importance of this pattern of gene expression for uterine function during estrous cycle and early pregnancy remains to be determined.
Technical Abstract: Previous gene mapping analyses revealed a quantitative trait locus for uterine capacity on chromosome 8. Comparison of porcine and human genetic maps suggests that the bone morphogenetic protein receptor IB (BMPR-IB) gene may be located near this region. The objectives of this study were to 1) clone the full coding region for BMPR-IB, 2) examine BMPR-IB gene expression by the endometrium and its cellular localization during the estrous cycle and early pregnancy and 3) map the BMPR-IB gene. By iterative screening of an expressed sequence tag library, we obtained a 3559 bp cDNA clone including the full coding region of BMPR-IB. Endometrial BMPR-IB mRNA expression of White composite gilts was determined by Northern blotting in Day 10, 13, and 15 cyclic, and Day 10, 13, 15, 20, 30, and 40 pregnant gilts. In cyclic gilts, endometrial BMPR-IB mRNA expression was elevated on Day 13 and 15 (P < 0.01), compared to Day 10. Expression of BMPR-IB mRNA was localized in both luminal and glandular epithelium on Day 15. However, in pregnant gilts, BMPR-IB mRNA expression was not significantly different in the endometrium from Day 10 to 20, and it was significantly decreased on Day 30 and 40 (P = 0.011). The BMPR-IB gene was mapped to 108 cM on chromosome 8. These findings show that BMPR-IB mRNA expression is temporally regulated during the estrous cycle and early pregnancy in gilts; this pattern of gene expression may be important for endometrial function during the estrous cycle and early pregnancy.