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

Research Authors
Hombach-Klonisch, S., Abd-Elnaeim, M. M., Skidmore, A., Allen, A., Leiser, R., Fisher, B., and Klonisch, T.
Research Abstract

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.

Research Journal
Biology of Reproduction
Research Rank
2
Research Vol
Vol. 62,
Research Year
2000
Research Pages
PP. 839-846