Expression patterns of cytochrome P450 aromatase genes during ovary development and their responses to temperature stress in female yellow catfish (Pelteobagrus fulvidraco)

Abstract

Cytochrome P450 aromatase (P450arom) plays a pivotal role in ovary development. In this study, we used semi-quantitative reverse transcription PCR (RT-PCR) to analyze spatiotemporal expressions of two P450arom genes (CYP19A and CYP19B) and their responses to temperature stress in female yellow catfish (Pelteobagrus fulvidraco). Tissue distribution pattern of CYP19 showed that CYP19B was abundantly expressed in fish brain and ovary (brain > ovary), but weakly in intestines, whereas CYP19A was exclusively expressed in ovary. Semi-quantitative RT-PCR analyses showed high transcript abundance of both CYP19A and CYP19B in the ovarian reproductive cycle, corresponding with serum estradiol-17β (E 2 ) levels. Increases in aromatases, serum E 2 and testosterone (T) levels in fish exposed to higher temperature indicated stimulation of ovarian maturation and recrudescence by heat stress in stages Ⅱ and Ⅴ during the ovarian cycle, whereas associated decreases in stage Ⅲ suggested vitellogenesis inhibition by heat stress. Gene expression of CYP19 was closely related to levels of serum E 2 . Results demonstrated CYP19 played a crucial role in the reproductive cycle of female yellow catfish. Different temperature stress affected CYP19 gene expression in the fish ovarian reproductive cycle. Associated P450arom genes could be useful for studying physiological aspects of yellow catfish.

RETRACTED: Estrogen‐regulated expression of P450arom genes in the brain and ovaries of adult female Indian climbing perch, Anabas testudineus

“…Such overlapping expressions of aromatase mRNAs in the ovary and brain in some teleost compared to others where there are restricted expression may be explained by species‐specific differences related to further gene speciatization, gonadal develpment, and reproductive strategy, individual fish differences, and age or method of detection employed (Berney et al., ; Roy Moulik et al., ). The absence of both the mRNAs in kidney in our study is not consistent with earlier reports in Nile tilapia and Yellow catfish (Chang et al., ; Miao et al., ). Other tissues, particlarly eyes and liver in A. testudineus also showed mRNA expressions of one or other isoforms, although the results are not always consistent among species (Piferrer & Blázquez, ).…”

“…European sea bass (González & Piferrer, 2003), Japanese eel (Anguilla japonica) (Ijiri et al, 2003), yellow catfish (Miao et al, 2011), and…”

“…Predominant expression of cyp19a1b in brain and cyp19a1a in ovary of A. testudineus has similarly been reported in many other teleosts (Barney et al., ; Chang et al., ; Kishida & Callard, ; Roy Moulik et al., ; Sawyer et al., ; Wong et al., ). In southern catfish and yellow cat fish cyp19a1a , however, was exclusively found in ovary, while cyp19a1b was expressed both in brain and ovary with higher expression in brain (Liu et al., ; Miao et al., ). In rainbow fish, Melanotaenia fluviatilis , cyp19a1a was restricted to ovaries with no measurable expression in any other tissues (Shanthanagouda et al., ).…”

“…Therefore, P450arom gene expression both in brain and ovary is correlated with translation of aromatase protein and aromatase activity. In medaka (Fukada et al., ), red sea beam (Gen et al., ), European sea bass (González & Piferrer, ), Japanese eel ( Anguilla japonica ) (Ijiri et al., ), yellow catfish (Miao et al., ), and Labeo rohita (Roy Moulik et al., ) P450arom gene expression also showed a relationship with oocyte development. Maximum expression of cyp19a1a in ovary and cyp19a1b in brain during peak reproductive period in this fish is consistent with the function of estrogen in ovarian development of adult fish (Blázquez & Piferrer, ; Kazeto et al., ; Miao et al., ; Tang et al., ).…”

“…In medaka (Fukada et al., ), red sea beam (Gen et al., ), European sea bass (González & Piferrer, ), Japanese eel ( Anguilla japonica ) (Ijiri et al., ), yellow catfish (Miao et al., ), and Labeo rohita (Roy Moulik et al., ) P450arom gene expression also showed a relationship with oocyte development. Maximum expression of cyp19a1a in ovary and cyp19a1b in brain during peak reproductive period in this fish is consistent with the function of estrogen in ovarian development of adult fish (Blázquez & Piferrer, ; Kazeto et al., ; Miao et al., ; Tang et al., ). Aromatase expression in gonad is a key step in the process of E2 synthesis, which is crucial for ovarian maturation and female reproduction in teleost (Guiguen et al., ).…”