HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal My Folders Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Fields, P. A. Articles by Fields, M. J. Search for Related Content PubMed PubMed Citation Articles by Fields, P. A. Articles by Fields, M. J. Agricola Articles by Fields, P. A. Articles by Fields, M. J.

B-Chain Sequence and In Situ Hybridization of the Rabbit Placental Relaxin-Like Gene Product

^a Department of Structural & Cellular Biology, University of South Alabama College of Medicine, Mobile, Alabama 36688 ^b Department of Cell Biology & Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas 79430 ^c Cell Biology Section, Laboratory of Pulmonary Pathobiology, NIEHS, NIH, Research Triangle Park, North Carolina 27709 ^d Department of Animal Science, University of Florida, Gainesville, Florida 32611

We reported that the nucleotide sequence of a cDNA generated from rabbit placental poly(A)⁺ RNA using porcine preprorelaxin primers was identical to SQ10, a product of squamous differentiated tracheal epithelial cells. However, these results did not confirm that SQ10 was the biologically active rabbit relaxin that had been isolated previously yet not sequenced. In this study, a 7-kDa protein isolated from rabbit placentas exhibited relaxin bioactivity and cross-reacted with a porcine relaxin antiserum. A partial amino acid sequence of this protein revealed a sequence identical to that of SQ10. Although the amino acid sequence of the putative relaxin receptor-binding domain found in the B chain of relaxin was modified in SQ10 from CGRDYVR to CRNDFVR, the placental protein was bioactive. These results suggest that SQ10 is the rabbit relaxin. In situ hybridization, using an SQ10 riboprobe, indicated radiolabeling in the syncytiotrophoblast cells of the rabbit placenta. The pattern of labeling corresponded with the immunohistochemical staining for relaxin observed with use of a porcine relaxin antiserum. These results indicate that the syncytiotrophoblast cells are a site of synthesis for SQ10 and that the immunostaining is not solely the result of sequestering SQ10 through receptor-mediated endocytosis. A potential role for relaxin in implantation is discussed.

¹ Correspondence: Phillip A. Fields, University of South Alabama College of Medicine, Department of Structural & Cellular Biology, MSB 1206, Mobile, AL 36688. FAX: 334 460 6771; pfields{at}usamail.usouthal.edu