Androgen receptors in the bonnethead, Sphyrna tiburo: CDNA cloning and tissue-specific expression in the male reproductive tract
Document Type
Article
Publication Date
12-1-2015
Abstract
As demonstrated in past studies, androgens appear to play critical roles in regulating reproduction in male sharks. However, little is known about the cell-specific actions of androgens in these fishes. To address this, this study examined androgen targets in reproductive organs of a seasonally reproducing shark, the bonnethead (Sphyrna tiburo). A partial bonnethead AR cDNA clone was isolated and found to exhibit strong homology with known vertebrate ARs. Using RT-PCR and in situ hybridization, AR was found to be expressed in multiple cell types in the male bonnethead testis (premeiotic germ cells, Leydig-like interstitial cells, Sertoli cells, peritubular myoid cells, and mature spermatozoa) and gonadal ducts (stromal cells, luminal epithelial cells, mature spermatozoa). Furthermore, AR expression in these organs was found to vary temporally in relation to the seasonal reproductive cycle. Based on immunocytochemistry, the presence of AR protein in male bonnethead reproductive organs was largely consistent with patterns of AR gene expression with the single exception of mature spermatozoa, which exhibited consistently strong mRNA expression but only inconsistent and weak AR protein immunoreactivity. These results suggest important roles for androgens in regulating germ cell proliferation, hormone production, spermatid elongation, spermiation, and gonadal duct function in male bonnetheads. In addition, high abundance of AR mRNA in bonnethead spermatozoa suggest the potential for de novo protein synthesis following spermiation/copulation and/or a role for AR mRNA in early embryonic development, both of which have been proposed to explain the occurrence of mRNA transcripts in spermatozoa from various vertebrates.
Publication Title
General and Comparative Endocrinology
Volume
224
First Page
235
Last Page
246
Digital Object Identifier (DOI)
10.1016/j.ygcen.2015.08.018
PubMed ID
26320857
ISSN
00166480
E-ISSN
10956840
Citation Information
Tyminski, Gelsleichter, J. J., & Motta, P. J. (2015). Androgen receptors in the bonnethead, Sphyrna tiburo : cDNA cloning and tissue-specific expression in the male reproductive tract. General and Comparative Endocrinology, 224, 235–246. https://doi.org/10.1016/j.ygcen.2015.08.018