|Kim, Jong - FORMER ARS EMPLOYEE|
Submitted to: Midwestern Section of the American Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: December 13, 2005
Publication Date: August 20, 2006
Repository URL: http://www.asas.org/abstracts/2006sectional/index.htm
Citation: Vallet, J., Kim, J. 2006. Placental expression of the membrane form of folate binding protein during pregnancy in swine [abstract]. Journal of Animal Science. 84 (Supplement 2):129-130. (Abstract #308) Technical Abstract: Previous experiments indicated that secreted (s) and membrane (m) forms of folate binding protein (FBP) are present in the intrauterine environment of the pig. Our studies indicated that the two forms are produced sequentially, the secreted form is present in the intrauterine glands until day 20 of gestation, while binding analysis indicated that placental folate binding increased dramatically in placental membranes until day 50 of gestation. However, the cell types expressing the membrane form of FBP have not been investigated. In this experiment, uterine wall sections from days 35, 50, 70, 90 and 105 of gestation were collected at slaughter and fixed in 4% paraformaldehyde in PBS. Samples were dehydrated through a graded series of alcohol and xylene and then imbedded in paraffin. Sections were cut (6 microns), placed on slides, and the slides were subjected to in situ hybridization analysis for mFBP using an **35S-labelled probe that was specific to the 3' end of the mFBP mRNA. Slides were then dehydrated, dipped in NTB2 emulsion, dried, allowed to expose for 2 weeks, developed, and counterstained with hematoxylin. Silver grains were clearly and uniformly evident over the placental epithelium, including both the tall columnar epithelium at the top of placental folds, and the cuboidal epithelium present in the sides and bottom of placental folds. The strength of labeling appeared to be uniform throughout gestation. These results indicate that the placenta expresses mFBP from day 35 of gestation onward, consistent with our previous folate binding results. This expression is consistent with the concept that sFBP and mFBP occur sequentially during gestation in swine, and that placental mFBP expression plays a role in folate transport after the placenta forms between day 20 and 35 of gestation. This project was supported by National Research Initiative Competitive Grant No. 2001-35203-11241 from the USDA Cooperative State Research, Education, and Extension Service.