Submitted to: Biology of Reproduction Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: April 15, 2000
Publication Date: December 20, 2000
Citation: Kim, J.G., Vallet, J.L., Christenson, R.K. 2000. Characterization of uterine epidermal growth factor during early pregnancy in pigs [abstract]. Biology of Reproduction. 62(Supplement 1):310-311. (Abstract No. 517) Technical Abstract: Uterine capacity is a component contributing to litter size in swine. Genome mapping revealed a quantitative trait locus for uterine capacity located on porcine chromosome 8. Epidermal growth factor (EGF) gene is located on chromosome 8 and has been reported to stimulate epithelial cell growth. EGF has been reported in porcine endometrium, but changes in mRNA levels in endometrium have not been reported. Partial cDNA sequences of porcine EGF have been reported previously. Objectives of this study were to 1) clone full-length cDNA of EGF and 2) determine its changes in expression during pregnancy. Using reverse transcription-polymerase chain reaction and iterative screening of a porcine reproductive tissue cDNA library, we obtained 4917 bp of cDNA sequence of porcine EGF. It included the entire coding region. This is the first report of the full coding region of porcine EGF. The predicted protein sequence of the EGF precursor contains 1215 amino acids, similar to that of human EGF (1207 amino acids, 81% identity). Expression of EGF mRNA in the endometrium of White crossbred gilts (n=3-5 each) was determined by Northern blotting. Twenty ug of total RNA from endometrium of d 10, 13 and 15 cyclic gilts and 10, 13, 15, 20, 30 and 40 of pregnant gilts were used for Northern blotting. A probe consisting of 3349 bp of the coding region of EGF was used to detect the EGF mRNA. The bands corresponding to EGF mRNA were determined by densitometry and results were analyzed by ANOVA. EGF mRNA expression tends to decrease gradually during the estrous cycle and pregnancy with significant drops from d 13-15 (p=.04) and from d 30-40 (p=.01). These findings show EGF mRNA expression is temporally regulated. This pattern of gene expression may be important during early conceptus development.