Expression of mRNA and protein localization of epidermal growth factor and its receptor in goat ovaries

Abstract

To examine the possibility that epidermal growth factor (EGF) and its receptor (EGF-R) are expressed throughout folliculogenesis, we studied the presence and distribution of EGF and EGF-R in goat ovaries. Ovaries of goats were collected and either fixed in paraformaldehyde for immunohistochemical localization of proteins, or used for the isolation of follicles, luteal cells and ovarian surface epithelium to study mRNA expression for EGF and EGF-R, using the reverse transcriptase polymerase chain reaction. EGF protein and mRNA were found in primordial, primary and secondary follicles as well as in small and large antral follicles and in surface epithelium, but in corpora lutea only the protein could be detected. Antral follicles expressed EGF mRNA in oocyte, cumulus, mural granulosa and theca cells. For EGF-R, both protein and mRNA were present at all stages of follicular development and in all antral follicular compartments. EGF-R protein and mRNA were also found in corpora lutea and surface epithelium. It is concluded that EGF and its receptor are expressed in goat ovarian follicles at all stages of follicle development, in corpora lutea, and in ovarian surface epithelium.

Steady-state level of epidermal growth factor (EGF) mRNA and effect of EGF on in vitro culture of caprine preantral follicles

“…The presence of mRNA for EGF and FSH receptors has been observed in caprine secondary follicles (EGF-R: Silva et al 2006, FSH-R: Saraiva et al 2010a, the binding of Fig. 5 Daily growth rate of morphologically normal follicles during in vitro culture for 6 days.…”

“…Among these factors, the epidermal growth factor (EGF) has been highlighted; it has emerged as an important substance capable of inducing follicular development in vitro (Celestino et al 2009). EGF is a protein belonging to the EGF family, which consists of at least eight members (Riese and Stern 1998), and is considered a mitogenic factor, being involved in the regulation of several ovarian processes (Silva et al 2006), including proliferation and cellular differentiation, in addition to steroidogenesis (Saha et al 2000;Wang et al 2007). The expression of protein and mRNA for EGF has been demonstrated in the oocyte and granulosa cells of early and late-staged follicles (hamster: Roy and Greenwald 1990;human: Maruo et al 1993;Bennett et al 1996;pig: Singh et al 1995), whereas EGF mRNA has been described only in oocyte and granulosa cells from pig antral follicles (Singh et al 1995).…”

“…The expression of protein and mRNA for EGF has been demonstrated in the oocyte and granulosa cells of early and late-staged follicles (hamster: Roy and Greenwald 1990;human: Maruo et al 1993;Bennett et al 1996;pig: Singh et al 1995), whereas EGF mRNA has been described only in oocyte and granulosa cells from pig antral follicles (Singh et al 1995). In goats, the protein and mRNA for EGF are expressed in all developmental stages of ovarian follicles and in the ovarian surface epithelium (Silva et al 2006). However, the quantification of the steady-state level of EGF mRNA during the various stages of follicular development has not yet been performed.…”

“…The action of EGF in the ovary is mediated by a membrane receptor, EGF-R (ErbB1), which belongs to the ErbB superfamily (Riese and Stern 1998). EGF-R mRNA and protein have been identified in the oocyte and granulosa cells of earlyand late-stage follicles (rat: Chabot et al 1986;Feng et al 1987;human: Maruo et al 1993;Bennett et al 1996;Qu et al 2000;pig: Singh et al 1995;cattle: Lonergan et al 1996;mouse: Hill et al 1999;hamster: Garnett et al 2002;caprine: Gall et al 2004;Silva et al 2006). In hamsters, the expression of the protein and mRNA for the EGF receptor has been demonstrated to be positively regulated by gonadotropins and steroids (Garnett et al 2002).…”

Short-Term Culture of Ovarian Cortical Strips From Capuchin Monkeys (Sapajus apella): A Morphological, Viability, and Molecular Study of Preantral Follicular Development In Vitro

“…17 Except for the studies such as those from Nilsson and Skinner, 16 Abir et al, 12 and Silva et al, 18 assessment of follicular development is mainly or exclusively based on morphological and viability parameters. 15,17 Viable and morphologically normal follicles are, however, not unconditionally able to further develop into more advanced stages, since they might be functionally unable to do so.…”