Expression of nuclear progesterone receptor and progesterone receptor membrane components 1 and 2 in the oviduct of cyclic and pregnant cows during the post-ovulation period

Abstract

BackgroundProgesterone (P4) may modulate oviductal functions to promote early embryo development in cattle. In addition to its nuclear receptor (PR), P4 may mediate its actions through P4 receptor membrane component 1 (PGRMC1) and its relative, PGRMC2. Two successive experiments were undertaken to characterise the expression of PR, PGRMC1 and PGRMC2 in the bovine oviduct during the post-ovulation period, and to relate their expression to the presence of an embryo, the proximity of the CL and to the region of the oviduct.MethodsIn the first experiment (Exp. I), whole oviduct sections were collected from Holstein cows at Day 1.5, Day 4 and Day 5 post-ovulation (n = 2 cows per stage). The expression of PR, PGRMC1 and PGRMC2 was studied in the ampulla and isthmus by RT-PCR, western-blot and immunohistochemistry. In Exp. II, oviduct epithelial cells were collected from cyclic and pregnant Charolais cows (n = 4 cows per status) at Day 3.5 post-ovulation and mRNA expression of PR, PGRMC1 and PGRMC2 was examined in the ampulla and isthmus by real-time quantitative PCR.ResultsIn Exp. I, PR, PGRMC1 and PGRMC2 were expressed in all oviduct samples. PGRMC1 was mainly localised in the luminal epithelium whereas PR and PGRMC2 were localised in the epithelium as well as in the muscle and stroma layers of the oviduct. The expression was primarily nuclear for PR, primarily cytoplasmic for PGRMC1 and both nuclear and cytoplasmic for PGRMC2. In Exp. II, mRNA levels for PR, PGRMC1 and PGRMC2 were not affected by either the pregnancy status or the side relative to the CL. However, the expression of PR and PGRMC2 varied significantly with the region of the oviduct: PR was more highly expressed in the isthmus whereas PGRMC2 was more highly expressed in the ampulla.ConclusionsThis is the first evidence of PGRMC2 expression in the bovine oviduct. Our findings suggest that P4 regulates the functions of the bovine oviduct in a region-specific manner and through both classical and non classical pathways during the post-ovulation period.

Expression and localization of progesterone receptor membrane component 1 and 2 and serpine mRNA binding protein 1 in the bovine corpus luteum during the estrous cycle and the first trimester of pregnancy

“…Moreover, this protein has been proposed to be involved in oviduct function [25], preterm labor [26], and carcinogenesis [27].…”

New Insight into Progesterone-dependent Signalization

“…Decreased expression of this membrane receptor seems to be one of the key factors necessary for the initiation of parturition [55,71]. PGRMC1 with PGRMC2 are probably involved in the functioning of oviduct smooth muscles, and they form a proper environment conducive to conception and oocyte transport, what has been proven already in cows [12]. In males, both isoforms could mediate in the acrosome reaction induced by P4 [26,72].…”

“…Another member of this family -neudesin, has been also identified in mammals [26]. PGRMC1 is localized principally in the epithelium, within cell membrane, cytosol and nucleus, and also in endoplasmic reticulum and Golgi apparatus [12,55]. Its expression has been demonstrated in many organs, i.e.…”

“…Two basic receptor isoforms are nPRA and nPRB, encoded by the same gene but characterized by distinct initiation sites of translation [9,10,12]. The primary structure of the nPR receptor is composed of domains with different conservativeness.…”

“…Both, PGRMC1 and the closely related PGRMC2 receptor, belong to the family of receptors associated with membranes (MAPR) [12,26,54]. Their homologues belonging to the MAPR genes family appear also in other Eucaryota, including nematodes, insects, yeast, and Arabidopsis thaliana.…”