Molecular characterization and sex-specific tissue expression of estrogen receptor α (esr1), estrogen receptor βa (esr2a) and ovarian aromatase (cyp19a1a) in yellow perch (Perca flavescens)

Yellow perch (Perca flavescens) exhibits an estrogen-stimulated sexual size dimorphism (SSD) wherein females grow faster and larger than males. To aid in the examination of this phenomenon, the cDNA sequences encoding estrogen receptor-α (esr1), estrogen receptor-βa (esr2a) and ovarian aromatase (cyp19a1a) for the teleost yellow perch were obtained. Several tissues were analyzed from both male and female adult yellow perch for sex-specific tissue expression. The full length cDNAs of yellow perch esr1, esr2a and cyp19a1a consist of 3052 bp, 2462 bp and 1859 bp with open reading frames encoding putative proteins of 576 amino acids, 555 amino acids and 518 amino acids, respectively. Esr1 and esr2a expression was highest in female ovary and liver tissues with low to moderate expression in other tissues. Esr2a showed a more global tissue expression pattern than esr1, particularly in males but also in females. Cyp19a1a expression was highest in both male and female spleen tissue and oocytes with moderate expression in male pituitary and gill tissue. Cyp19a1a expression was moderately high in female liver tissue with undetectable expression in male liver tissue, suggesting its involvement in sexually dimorphic growth. These sequences are valuable molecular tools that can be used in future studies investigating estrogen mechanisms and actions, such as SSD, in yellow perch.