Cloning and expression of SOLD1 in ovine and caprine placenta, and their expected roles during the development of placentomes

Ovine and caprine SOLD1 mRNAs have 303 bp open reading frames and encode for deduced SOLD1 proteins with 100 amino acids, including a 22-aa-long signal peptide at the N-terminal. Both of the SOLD1 amino acid sequences have high similarities with the bovine sequence. Both SOLD1 mRNAs were also expressed in TMCs of cotyledons and intercotyledonary membranes. The mature SOLD1 proteins were localized in the mesenchymal villi of cotyledons after secretion. Bovine, ovine and caprine SOLD1 affected gene expression in mesenchymal fibroblasts in vitro; nucleoredoxin expression was upregulated and BCL2-like 13 was downregulated. Thus, we suggest that SOLD1 acts as a modulator of cell proliferation and apoptosis.Expressing cells and protein localization of SOLD1 coincided among the three ruminants. SOLD1 participated in regulating nucleoredoxin and BCL2-like 13 expression in chorionic fibroblasts. SOLD1 is produced specifically in the cotyledons and intercotyledonary membranes in ruminants and appears to be involved in the construction of the ruminant placenta.We recently reported bovine secreted protein of Ly-6 (lymphocyte antigen-6, Ly-6/urokinase-type plasminogen activator receptor, uPAR) domain 1, SOLD1, as a lining protein that might participate in the formation of cotyledonary villi [1]. Ruminants such as cattle, sheep and goats, have a cotyledonary placenta. Here we aimed to explore the expression of SOLD1 in sheep and goat placentas and to clarify its roles in the ruminant placenta. We examined gene regulation of chorionic fibroblasts cultured with SOLD1 in vitro. We also compared SOLD1 protein characterization and roles among sheep, goats and cattle.The Ly-6 domain is a 70-100 amino acid (aa) long protein characterized by a conserved pattern of 8-10 cysteine residues with a defined pattern of disulfide bonding [2,3]. The Ly-6 superfamily comprises membrane type glycosylphosphatidylinositol (GPI)-anchored proteins and secreted proteins [2,4]. The secreted members lack