Submitted to: Keystone Symposia
Publication Type: Proceedings
Publication Acceptance Date: December 6, 2006
Publication Date: N/A
Technical Abstract: In pigs, about 20% embryonic loss is observed after artificial insemination or natural mating during peri-implantation and is coincident with rapid embryo elongation. The objective of the present study was to establish a comprehensive profile of abundant proteins and identify the expression pattern linked to specific stages of elongation. For that, the proteomes of a homogenous population of gestational day 11ovoid (Ovd; 0.7-1cm) and gestational day 12 filamentous (Fil; 15-20 cm) porcine embryos was compared. Proteins were extracted from 3 individual embryo pools (10 embryos/ pool) by a thiourea/urea buffer and then methanol/chloroform precipitated. Proteins were resolved by isoelectrofocusing in pH range 4-7 followed by 2-dimensional polyacrylamide gel electrophoresis. Colloidal coomassie blue stained gels were scanned with a laser densitometer (PDSI) and the image analysis was performed with the ImageMaster software. Protein spot intensities across six replicate gels were evaluated statistically and yielded a correlation r2 = 0.88 (Ovd) and 0.90 (Fil). A total of 380 and 310 aligned protein spots were detected for Ovd and Fil embryos, respectively. An in-gel trypsin digestion of protein was done and peptides were analyzed by MALDI-TOF or MS/MS; proteins were identified via the Mascot search engine. Proteins that were identified fell into the following functional categories: cytoskeleton, metabolism, stress response, and cell proliferation/differentiation. A comparison of protein expression with prior global transcriptomic analysis allows the determination of similarities or differences in regulation of a protein and its mRNA. Considering proteins are the physiologically active molecules, establishment of the proteome will enable better discernment of the biology underlying embryo development. This work was supported by USDA-ARS Current Research Information System Project No. 1265-31000-082-00D.