Expression of estrogen receptor‐α and ‐β mRNA in the brain of Japanese quail embryos

Abstract

The present study was conducted to investigate the mRNA expression of the two estrogen receptor (ER) subtypes ERalpha and ERbeta in the brain of Japanese quail embryos. We found expression of both ERalpha and ERbeta mRNA in homogenate of whole head from 6-day-old embryos, and in brain homogenate from 9- and 12-day-old embryos using real-time PCR. In 9- and 12-day-old embryos the ERalpha expression was higher in females than in males. We used in situ hybridization to examine the localization of the ERs in sections from male and female brains on day 9 and day 17 of incubation. On day 9, ERbeta mRNA was detected in the developing medial preoptic nucleus (POM), in the medial part of the bed nucleus of the striae terminalis (BSTm), and in the tuberal region of the hypothalamus. ERalpha signal could not be detected in the POM, the BSTm or the tuberal region in 9-day-old embryos. In 17-day-old embryos, ERbeta was highly expressed in the preoptic area, the nucleus Taeniae of the Amygdala (TnA) and the BSTm. Expression of ERalpha mRNA was detected in parts of the preoptic area and in the telencephalic TnA. No ERalpha expression was found in the BSTm, an area known to be sexually dimorphic in adults. The high embryonic expression of ERbeta in brain areas linked to sexual behavior indicates that ERbeta plays a role in sexual differentiation of the Japanese quail brain.

Multidimensional quantitative analysis of mRNA expression within intact vertebrate embryos

“…Current approaches employ some combination of microdissection (Nawshad et al, 2004;Redmond et al, 2014;Treutlein et al, 2014), cell dissociation (Manoli and Driever, 2012;Jean et al, 2015;Petropoulos et al, 2016), homogenization (Axelsson et al, 2007;de Jong et al, 2010;Pena et al, 2014), fluorescenceactivated cell sorting (Manoli and Driever, 2012;Treutlein et al, 2014;Allison et al, 2016), magnetic-activated cell sorting (Treutlein et al, 2014;Allison et al, 2016;Taylor et al, 2016) or lysis (Nawshad et al, 2004;de Jong et al, 2010;Laranjeiro and Whitmore, 2014;Redmond et al, 2014;Treutlein et al, 2014;Jean et al, 2015;Allison et al, 2016;Petropoulos et al, 2016), followed by RNA quantitation using quantitative real-time polymerase chain reaction (qPCR) (Nawshad et al, 2004;Axelsson et al, 2007;Laranjeiro and Whitmore, 2014;Pena et al, 2014;Jean et al, 2015), RNA sequencing (Treutlein et al, 2014;Allison et al, 2016;Petropoulos et al, 2016), in situ hybridization flow cytometry (Allison et al, 2016;Taylor et al, 2016), microarray hybridization (de Jong et al, 2010;Redmond et al, 2014;Jean et al, 2015) or hybridization barcoding (Laranjei...…”

Age‐dependent differential expression of genes involved in steroid signalling pathway in the brain of protandrous black porgy, Acanthopagrus schlegeli

“…The major role of estrogens and aromatase in natural sex change in black porgy was demonstrated by aromatase inhibitor (AI) treatment (Lee et al, 2002). Estrogens exert biological effects by interacting with estrogen receptors (esrs), esr1 (ERa; Green et al, 1986), esr2a (ERb; Kuiper et al, 1996;Tremblay et al, 1997) and esr2b (in teleosts, ERb2 or ERc; Hawkins et al, 2000;Menuet et al, 2002), which belong to the superfamily of steroid hormone receptors and act as ligand-activated transcription factors (Axelsson et al, 2007). Besides, there are also documented actions through nonclassical estrogen receptor pathways.…”

Distribution and sex differences in aromatase-producing neurons in the brain of Japanese quail embryos

“…1988b; Ottinger et al, 2001), and, as this study showed, the sex differences in ARO-immunoreactivity are fully reversed by estradiol treatment of male embryos in both the POM and BSTM. Consistently, the developing POM and the BSTM are very rich in 17b-estradiol receptors that may mediate, at least in part, the effects of estradiol on these nuclei (Axelsson et al, 2007). These data, taken together, indicate that the estrogenic hormonal milieu mediates the onset of sexual differences in ARO-immunoreactivity.…”