title: RNA-seq analysis of equine conceptus transcripts during embryo fixation and capsule disappearance.
abstract: Extensive studies have been conducted to characterize the unique phenomena of equine pregnancy. Most studies have focused on embryo transmigration when the embryo is covered with a mucin-like glycoprotein capsule and on the characterization of the chorionic girdle and chorionic gonadotropin (CG) secretion. However, the events preceding and following capsule disappearance have not been well studied. In this study, the mRNA expression in conceptus membranes at days 19, 21, and 25 (day 0 = day of ovulation) was analyzed by RNA-seq (SOLiD3), and transcript levels on these three days and day 13 were confirmed by real-time PCR. Of the 26,416 equine genes registered, 20,436 transcripts were aligned to sequences in the Ensembl database, from which 4,625 transcripts were registered in both Ensembl and the KEGG pathway. Each of the 4,625 transcripts was examined through KEGG pathway analysis, and 12 transcripts of integrins (ITGs) and collagens (COLs) were confirmed through real-time PCR. Our data indicated that extracellular matrix (ECM)-related mRNAs were highly expressed in day 19, 21, and 25 conceptus membranes. In combination with previous results, which confirmed a lack of laminin and fibronectin transcript expression in the endometrium, these observations suggest that in contrast to attachment through focal adhesion, conceptus chorionic membrane ECMs function as a scaffold-like structure to possibly maintain the shape of the conceptus and a separation between chorionic membranes and the uterine luminal epithelium.
authors.affiliation: Laboratory of Theriogenology and Animal Breeding, Veterinary Medical Sciences, The University of Tokyo, Tokyo, 113-8657 Japan; Laboratory of Cellular Biochemistry and Animal Resource Center, Veterinary Medical Sciences, The University of Tokyo, Tokyo, 113-8657 Japan.
authors.forename: Yurika
authors.initials: Y
authors.lastname: Tachibana
authors.affiliation: Laboratory of Theriogenology and Animal Breeding, Veterinary Medical Sciences, The University of Tokyo, Tokyo, 113-8657 Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Sakurai
authors.affiliation: Laboratory of Theriogenology and Animal Breeding, Veterinary Medical Sciences, The University of Tokyo, Tokyo, 113-8657 Japan.
authors.forename: Hanako
authors.initials: H
authors.lastname: Bai
authors.affiliation: Laboratory of Cellular Biochemistry and Animal Resource Center, Veterinary Medical Sciences, The University of Tokyo, Tokyo, 113-8657 Japan.
authors.forename: Kunio
authors.initials: K
authors.lastname: Shiota
authors.affiliation: Hidaka Training and Research Center, Japan Racing Association, Urakawa, 057-0171 Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Nambo
authors.affiliation: Laboratory of Veterinary Physiology, Department of Veterinary Medicine, Tokyo University of Agriculture and Technology, Fuchu, 183-8509 Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Nagaoka
authors.affiliation: Laboratory of Theriogenology and Animal Breeding, Veterinary Medical Sciences, The University of Tokyo, Tokyo, 113-8657 Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Imakawa
mesh_terms: D000818:Animals; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D005260:Female; D020869:Gene Expression Profiling / Q000662:veterinary; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D006736:Horses / Q000196:embryology* / Q000235:genetics*; D008969:Molecular Sequence Data; D011247:Pregnancy; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D017423:Sequence Analysis, RNA / Q000662:veterinary; D015053:Zygote / Q000737:chemistry*
chemical_list: D017931:DNA Primers; D016326:Extracellular Matrix Proteins