To examine the differential expression of proteins during the cycling (70～80% confluences) and G0/G1 (full confluences) phases in porcine fetal fibroblast cells, we used a global proteomics approach by 2‐D gel electrophoresis (2‐DE) and MALDI‐TOF‐MS. Cycling cell were harvested at approximately 70% to 80% confluent state while cells in G0/G1 phase were recovered after maintenance of a confluent state for 48 hr. Cellular proteins with isoelectric points ranging between 3.0～10.0, were analyzed by 2‐DE with 2 replicates of each sample. A total of approximately 700 spots were detected by 2‐D gels stained with Coomassie brilliant blue. On comparing the cell samples obtained from the cycling and G0/G1 phases, a total of 13 spots were identified as differentially expressed proteins, of which 8 spots were up‐regulated in the cycling cell and 5 were up‐regulated in the G0/G1 phase. Differentially expressed proteins included K3 keratin, similar to serine protease 23 precursor, protein disulfide‐isomerase A3, microsomal protease ER‐60, alpha‐actinin‐2, and heat‐shock protein 90 beta. The identified proteins were grouped on the basis of their basic functions such as molecular binding, catabolic, cell growth, and transcription regulatory proteins. Our results show expression profiles of key proteins in porcine fetal fibroblast cells during different cell cycle status.

Pregnancy is a unique event in which a fetus develops in the uterus despite being genetically and immunologically different from the mother, and the underlying mechanisms remain poorly understood. To analyze the differential gene expression profiles in nonpregnant and 7 days post coitus (dpc) pregnant uterus of mice, we performed a global proteomic study by 2‐D gel electrophoresis (2‐DE) and MALDI‐TOF‐MS. The uterine proteins were separated using 2‐DE. Approximately 1,000 spots were detected on staining with Coomassie brilliant blue. An image analysis using Melanie III (Swiss Institute for Bioinformatics) was performed to detect variations in protein spots between pregnant and nonpregnant uterus. Twenty‐one spots were identified as differentially expressed proteins, of which 10 were up‐regulated proteins such as alpha‐fetoprotein, chloride intracellular channel 1, transgelin, heat‐shock protein beta‐1, and carbonic anhydrase II, while 11 were down‐regulated proteins such as X‐box binding protein, glutathione S‐transferase omega 1, olfactory receptor Olfr204, and metalloproteinase‐disintegrin domain containing protein TECADAM. Most of the identified proteins appeared to be related with catabolism, cell growth, metabolism, regulation, cell protection, protein repair, or protection. Our results uncovered key proteins of mouse uterus involved in pregnancy.