Characterization of uterine epidermal growth factor during early pregnancy in pigs☆

Abstract

Genomic research has identified a quantitative trait locus for uterine capacity, a component trait contributing to litter size, on porcine chromosome 8. The epidermal growth factor (EGF) gene, on porcine chromosome 8, may influence uterine capacity because of its growth-promoting activities. Using reverse transcription-polymerase chain reaction (PCR) and iterative screening of a porcine reproductive tissue cDNA library, 4932 bp cDNA sequence coding for porcine EGF precursor was obtained. The predicted protein sequence of the EGF precursor contained 1214 amino acids, similar to human EGF precursor (1207 amino acids, 81% identity). Curiously, the sequence of the mature peptide was less homologous between species than other regions of EGF precursor. The presence of conserved regions outside the mature peptide may suggest that these regions are functionally important. Expression of EGF mRNA in the endometrium of White crossbred gilts (n = 3 to 5 each) was determined by Northern blotting using 20 microg of total RNA from endometrium of D 10, 13, and 15 cyclic, and D 10, 13, 15, 20, 30, and 40 of pregnant gilts. A 3342 bp probe from EGF precursor was used. The bands corresponding to EGF mRNA were quantified by densitometry and results were analyzed by ANOVA. EGF mRNA expression decreased significantly from D 13 to 15 of the cycle and pregnancy (P = 0.04), and from D 30 to 40 of pregnancy (P = 0.01). These findings show that EGF mRNA expression is temporally regulated during the cycle and early pregnancy, and this pattern of gene expression may be important during early conceptus development.

Vascular Endothelial (VEGF) and Epithelial Growth Factor (EGF) as Well as Platelet‐Activating Factor (PAF) and Receptors are Expressed in the Early Pregnant Canine Uterus

“…1998; Lennard et al. 1998; Kim et al. 2001) and in the present study, in the canine uterus and during all pregnancy stages.…”

“…They have been detected in the uterus of women, primates, horses, goats, pigs, mice and rats (Twardzik 1985;Stewart et al 1994;Flores et al 1998) and are mainly expressed during the pre-implantation and implantation period (Kennedy et al 1994). They influence early embryonic development, cleavage and differentiation of blastocysts (Han et al 1987;Bonvissuto et al 1992;Kim et al 2001;Aflalo et al 2007). During implantation of human embryos, EGF is synthesized by endometrium cells and enhances embryo invasion by binding to EGF receptor on the cytotrophoblast surface (Bass et al 1994).…”

Epidermal growth factor stimulates proliferation and migration of porcine trophectoderm cells through protooncogenic protein kinase 1 and extracellular-signal-regulated kinases 1/2 mitogen-activated protein kinase signal transduction cascades during early pregnancy

“…Among essential growth factors during early pregnancy, EGF is known to influence uterine capacity since location of the gene for the EGF precursor is very near a quantitative trait locus for uterine capacity in pigs (Kim et al, 2001). Both EGF and EGFR are expressed in pregnant uteri of various mammalian species such as human (Chegini et al, 1986;Smith et al, 1991), baboon (Slowey et al, 1994), rhesus monkey (Yue et al, 2000), rabbit (Hofmann and Anderson, 1990), mouse (Das et al, 1994) and pigs (Kim et al, 2009(Kim et al, , 2001Wollenhaupt et al, 2004;Kennedy et al, 1994), and it is present at high concentration in various body fluids.…”

Generation of epidermal growth factor–expressing Lactococcus lactis and its enhancement on intestinal development and growth of early-weaned mice

“…Reverse transcription and polymerase chain reactions were carried out by using forward (5#-GCTCCGAGATCTAATAGTTAC-TCTGAATGC-3#) and reverse (5#-GAGAATCTGCAGCTAG-CGCAGCTCCCACCATTT-3#) primers to amplify the mature EGF sequence [GenBank NM_214020 (19); bold letters indicate the addition of restriction enzyme sites of BglII and PstI in the forward and reverse primers, respectively]. Polymerase chain reaction (PCR) conditions were 94°C (3 min) [94°C (45 s), 58°C (30 s), and 72°C (1.5 min)] for 35 cycles and 72°C (10 min) for the final extension.…”