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United States Department of Agriculture

Agricultural Research Service

Title: Pig Lines Genetically Selected for Component Traits of Litter Size Exhibit Differential Gene Regulation at the Onset of Embryo (Trophectoderm) Elongation

Authors
item Miles, Jeremy
item Blomberg, Le Ann
item Freking, Bradley
item Zuelke, Kurt

Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: April 21, 2005
Publication Date: May 12, 2005
Citation: This is a poster presentation for BARC Poster Day on 5/12/2005.

Technical Abstract: Significant embryonic (~18%) loss occurs in the pig as the pre-implantation embryo undergoes a dramatic morphological change from an ovoid (8-10 mm) at gestational Day 11 to a long, thin filament (<150 mm) by Day 12. Lines of pigs genetically selected for increased uterine capacity traits have improved embryonic survival and litter size, while pigs selected for increased ovulation rate have decreased embryo survival. Alternations in the expression of genes that play key roles in embryo elongation and maternal recognition of pregnancy may reflect differences in embryo survival and litter size observed in these lines of pigs. The objective of the current study was to compare gene expression regulation at the onset of porcine embryo elongation (gestational Day 11) in control animals (CO) and selected lines for uterine capacity (UC) or ovulation rate (OR). Total RNA was isolated from Day 11 ovoid embryos (CO, n = 5; UC, n = 5; OR, n = 5). Real-time PCR was utilized to measure the gene expression level of transcripts involved in developmentally important processes, such as steroidogenesis, cellular differentiation, cell-cell interaction and immune modulation. Expression of cytochrome P450scc (CYP11A) mRNA was decreased in embryos from the OR and UC lines compared with controls. Similarly, expression of steroidogenic acute regulatory protein (STAR) mRNA tended to be decreased in embryos from the UC and OR lines compared with the CO line. Furthermore, 17'-hydroxylase (CYP17A1) and aromatase (CYP19A1) mRNA expression exhibited a differential pattern in embryos from all three lines (CO>UC>OR). In contrast, expression of cytokeratin 8 (KRT8) mRNA was increased in embryos from the UC and OR lines compared with controls. Expression of cytokeratin 18 (KRT18) mRNA also tended to be increased in embryos from the UC and OR lines compared with controls. Expression of galectin 1 (LGALS1) mRNA tended to be increased in embryos from the UC line compared with the OR line. Constitutive expression of 17'-hydroxysteroid dehydrogenase (HSD17B1), stratifin (SFN), interleukin-1' (IL1B) or IL1 receptor type 1 (IL1RT1) mRNA was seen in embryos from all three lines. These results demonstrate altered gene expression in embryos from pigs selected for increased uterine capacity and ovulation rate compared with controls which may reflect differences in embryo survival observed for these different lines of pigs.

Last Modified: 4/16/2014
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