Characterization of crab EcR and RXR homologs and expression during limb regeneration and oocyte maturation

• Published in: Molecular and cellular endocrinology Vol. 189; no. 1; pp. 59 - 76
• Main Authors: Durica, David S., Wu, Xiaohui, Anilkumar, Gopinathan, Hopkins, Penny M., Chung, Arthur C.-K.
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier Ireland Ltd 28.03.2002
• Subjects: Amino Acid Sequence; Animals; Brachyura - physiology; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Ecdysteroid receptor; Extremities - physiology; Gene Library; Genes, Reporter; Insect Proteins - genetics; Insect Proteins - metabolism; Invertebrate Hormones - genetics; Invertebrate Hormones - metabolism; Molecular Sequence Data; Nuclear Proteins - genetics; Nuclear Proteins - metabolism; Oocytes - physiology; Receptors, Retinoic Acid - genetics; Receptors, Retinoic Acid - metabolism; Receptors, Steroid - genetics; Receptors, Steroid - metabolism; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; Regeneration - physiology; Retinoid X Receptors; Retinoid-X receptor; Sequence Alignment; Transcription Factors - genetics; Transcription Factors - metabolism; Uca pugilator; Ultraspiracle; Retinoid-X receptor; Uca pugilator; Ecdysteroid receptor; Ultraspiracle
• ISSN: 0303-7207; 1872-8057
• DOI: 10.1016/S0303-7207(01)00740-7

We report here complete coding sequences for the Uca pugilator homologs of the ecdysteroid (UpEcR) and retinoid-X receptors (UpRXR). Library screenings recovered cDNA clones containing a unique amino terminal open-reading frame (A/B domain) for each gene, most similar to insect B1 EcR and USP1/RXR isoforms. Splicing variants in the UpRXR ligand-binding domain were also identified, in a region critical for folding of Drosophila and lepidopteran USP. UpEcR and UpRXR proteins were able to associate, and both are required for binding to an ecdysteroid HRE; these interactions were not hormone-dependent. Ribonuclease protection assays (RPA) were conducted using A/B domain and ‘common’ (C or E) domain probes on RNA isolated from various stages of regenerating limb buds and ovaries. For several of the limb bud and ovarian stages examined, the relative level of A/B domain sequence protected was significantly less than common domain suggesting alternative amino terminal isoforms other than those isolated through cloning. This is the first report of UpEcR and UpRXR transcription during ovarian maturation, implicating the ovary as a potential target for hormonal control in Crustacea.