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Abstract

Nonylphenol (NP) is a xenoestrogen whose estrogenic effects are mediated by the estrogen receptor (ER) in vertebrates. However, the ER appears to be absent in arthropods. Estrogen-related receptor (ERR) may be a candidate that responds to NP. To investigate the effects and mechanisms of NP in giant freshwater prawn Macrobrachium rosenbergii, a unique homolog of mammalian ERR was cloned from M. rosenbergii by rapid amplification of cDNA ends. The full length ERR cDNA consisted of 1897 bp with a 1374 bp open reading frame encoding 457 amino acid residues. RT-PCR analysis revealed that ERR was widely expressed in various tissues of male and female M. rosenbergii, including the brain ganglion, hepatopancreas, heart, and gonads. Interestingly, expression of ERR in ovaries was higher than that in testes. qPCR results showed high expression of ERR in ovaries at early developmental stages. NP exposure up-regulated the expression levels of ERR in the ovaries of M. rosenbergii in a time-dependent manner. The current study provides fundamental data to understand the response of ERR to NP exposure in M. rosenbergii. Aubin, 2001). It has been demonstrated that ERRs are constitutive transcriptional factors that activate expression of target genes via interactions with coactivators in the absence of exogenous ligands (Hong, Yang, & Stallcup, 1999; Schreiber, Knutti, Brogli, Uhlmann, & Kralli, 2003). Although the functions of ERRs are not well understood, they likely play important roles in animal reproduction, growth, development, and metabolism because their expression in embryonic and adult tissues occurs in very restricted spatiotemporal patterns (Giguère, 2002). In mammals, ERRs are involved in ER-dependent pathways related to the formation of bone and cancer development. For