title: Regucalcin is widely distributed in the male reproductive tract and exerts a suppressive effect on in vitro sperm capacitation in the water buffalo (Bubalus bubalis).
abstract: Regucalcin is a multi-functional, calcium-binding protein with roles in calcium homeostasis, apoptosis, cell proliferation, and free radical neutralization. Regucalcin is broadly expressed in the male reproductive organs of rat and bovine; here, we report its expression in the reproductive tract of male buffalo-especially in testis, epididymis, seminal vesicle, prostate, and bulbourethral gland of buffalo-as analyzed by real-time PCR, Western blot, and immunolocalization. Regucalcin degradation in seminal plasma, despite its high abundance in vesicular fluid, was demonstrated using recombinant regucalcin co-incubated with buffalo seminal plasma. This depletion of regucalcin appears to be related to its suppressive effect on in vitro sperm capacitation, observed using the chlortetracycline assay after treating buffalo spermatozoa with recombinant protein. Indeed, addition of recombinant regucalcin to capacitating media significantly reduced (P < 0.05) the percentage of capacitated spermatozoa to 6.1 ± 0.6 from 36.4 ± 1.8 in the untreated group. Taken together, the wide distribution of regucalcin in male buffaloes, versus its degradation in the seminal plasma and suppressive effects on in vitro capacitation of spermatozoa, indicate its possible anti-capacitation role in the reproductive tract. Mol. Reprod. Dev. 84: 212-221, 2017. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Division of Animal Biochemistry, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
authors.forename: Harikrishna
authors.initials: H
authors.lastname: Pillai
authors.affiliation: Division of Animal Biochemistry, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
authors.forename: Ashish Mukunda
authors.initials: AM
authors.lastname: Shende
authors.affiliation: Division of Physiology and Climatology, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
authors.forename: Mehtab Sing
authors.initials: MS
authors.lastname: Parmar
authors.affiliation: Division of Pathology, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
authors.forename: Anjaneya
authors.initials: A
authors.lastname: A
authors.affiliation: Theriogenology Laboratory, Animal Reproduction, Gynaecology and Obstetrics, National Dairy Research Institute, Karnal, Haryana, India.
authors.forename: Sreela
authors.initials: S
authors.lastname: L
authors.affiliation: Theriogenology Laboratory, Animal Reproduction, Gynaecology and Obstetrics, National Dairy Research Institute, Karnal, Haryana, India.
authors.forename: Arumugam
authors.initials: A
authors.lastname: Kumaresan
authors.affiliation: Division of Physiology and Climatology, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
authors.forename: Taru Sharma
authors.initials: TS
authors.lastname: G
authors.affiliation: Division of Animal Biochemistry, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
authors.forename: Sanjeev Kumar
authors.initials: SK
authors.lastname: Bhure
mesh_terms: D000818:Animals; D002020:Buffaloes / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D005837:Genitalia, Male / Q000378:metabolism*; D008297:Male; D059748:Proteolysis; D012661:Semen / Q000378:metabolism*; D013075:Sperm Capacitation; D013094:Spermatozoa / Q000378:metabolism*
chemical_list: D002135:Calcium-Binding Proteins