Expression of SOLD1 mRNA. (A) The expression levels of secreted protein of Ly-6 domain 1 (SOLD1) in bovine trophoblast (BT) cell lines (BT-A–L) in comparison with those in proximal fetal membranes (PFM), an in vivo control, and in BT-1, which was previously established, were analyzed by quantitative reverse transcription PCR (qRT-PCR). (B) The expression level of SOLD1 in BT cell lines. Expression of these mRNAs was normalized to the expression of GAPDH measured in the corresponding RNA preparation. The bar graph shows the means ± SEM values. Bars labeled with an asterisk (A) and different letters (B) are significantly different from each other (P < 0.05).