Ruminant relaxin in the pregnant one-humped camel (Camelus dromedarius)

• Published in: Biology of reproduction Vol. 62; no. 4; pp. 839 - 846
• Main Authors: Hombach-Klonisch, S, Abd-Elnaeim, M, Skidmore, J.A, Leiser, R, Fischer, B, Klonisch, T
• Format: Journal Article
• Language: English
• Published: Madison, WI Society for the Study of Reproduction 01.04.2000
• Subjects: Amino Acid Sequence; amino acid sequences; Animals; Base Sequence; Biological and medical sciences; Camelus - physiology; complementary DNA; Digoxigenin - metabolism; DNA - genetics; DNA - isolation & purification; dromedaries; Female; Fundamental and applied biological sciences. Psychology; gene expression; Hormone metabolism and regulation; immunohistochemistry; In Situ Hybridization; localization; messenger RNA; Molecular Sequence Data; nucleotide sequences; ovaries; Ovary - metabolism; placenta; Placenta - metabolism; precursors; Pregnancy; Pregnancy, Animal - physiology; Pregnancy. Parturition. Lactation; preprorelaxin; prorelaxin; relaxin; Relaxin - physiology; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - biosynthesis; RNA, Messenger - isolation & purification; uterine tissue; Uterus - metabolism; Vertebrates: reproduction; Nucleotide sequence; Fetal membrane; Ruminant animal; Camelus dromedarius; Gene expression; Relaxin; Ovarian hormone; Pregnancy; Ovary; Vertebrata; Mammalia; Placenta; Complementary DNA; Metabolic precursor; Uterus; Female genital system; Artiodactyla; Ungulata
• ISSN: 0006-3363; 1529-7268
• DOI: 10.1095/biolreprod62.4.839

We have determined the cDNA sequence of preprorelaxin in the pregnant one-humped camel by employing reverse transcription- and rapid amplification of cDNA ends-polymerase chain reaction. Camel preprorelaxin consisted of 600 base pairs (bp) encoding a protein of 199 amino acids (aa) with a signal peptide of 25 aa (75 bp), a B domain of 28 aa (84 bp), a C domain of 121 aa (366 bp), and an A domain of 24 aa (72 bp). The N terminus of the C domain of camel prorelaxin contained the unique proline-rich repetitive sequence (-RPAP) 3 -(-K/RPAL-) 2 , and within the B domain the classical -GRELVR- receptor binding motif was found. Camel preprorelaxin showed highest homology with porcine (74.6%) and equine (65.4%) relaxin. The ovary and the uteroplacental unit were a dual source of relaxin in the pregnant dromedary. Within the ovary, weak expression of relaxin was detected in large luteal cells of the mature corpus luteum. In the ovarian follicles, immunoreactive relaxin, but not relaxin mRNA, was detected in the granulosa and theca interna cell layer. Beginning at around Day 93 of gestation and coinciding with increasing interdigitation of the fetal villus with the underlying maternal endometrium, uterine luminal epithelial cells in the uteroplacental tissue expressed relaxin. Weak expression of immunoreactive relaxin, but not relaxin mRNA, was observed in villous trophoblast cells. Pseudostratified trophoblast cells at the base of the placental villi and multinucleate giant cells did not express relaxin.