Molecular cloning and expression analysis of a cDNAs encoding androgenic gland hormone precursors from two Porcellionidae species, Porcellio scaber and P. dilatatus

Male sexual characteristics in Crustacea are induced by androgenic gland hormone (AGH), which is produced by the male-specific androgenic gland. Recently, AGH in the terrestrial isopod Armadillidium vulgare was characterized and its cDNA cloned, the first example in which the structure of AGH was elucidated. We report here the molecular cloning of cDNAs encoding AGH precursors from two additional terrestrial isopods, Porcellio scaber and P. dilatatus. cDNA fragments encoding Porcellio scaber AGH (Pos-AGH) and P. dilatatus AGH (Pod-AGH) were amplified by RT-PCR using degenerate oligonucleotide primers designed based on the amino acid sequence of A. vulgare AGH (Arv-AGH). Subsequently, full length cDNAs were obtained by 5'- and 3'-RACE. Both AGH precursors consisted of a signal peptide, B chain, C peptide and A chain, and exhibited the same organization as that of Arv-AGH. The amino acid sequences of the A and B chains, which comprise mature AGH peptide, were highly conserved among the three species, while that of the C peptide showed only low sequence similarity. In Northern blot analysis, each cDNA fragment used as a probe specifically hybridized with a single band (0.75 kb) in mRNA extracted from whole male reproductive organs. In analysis of the tissue-specific gene expression of these two AGHs by RT-PCR, it was revealed that both AGH transcripts were detected only in cDNA synthesized using total RNA from the testis carrying the androgenic glands, but not in that from testis only, seminal vesicle, vas deferens, or hepatopancreas

Ligand-Selective Potentiation of Rat Mineralocorticoid Receptor Activation Function 1 by a CBP-Containing Histone Acetyltransferase Complex

The rat mineralocorticoid receptor (MR) has two activation functions in distinct regions of the A/B domain, designated activation function 1a (AF-1a; amino acids 1 to 169) and AF-1b (amino acids 451 to 600). Since the p160 family protein TIF2, a known component of the AF-2 coactivator complex, potentiates the transactivation function of AF-1b but not that of AF-1a, it is likely that some other, novel protein complex interacts with the AF-1a region. Therefore, we attempted to identify such coactivator complexes from HeLa nuclear extracts by biochemical purification using a glutathione S-transferase-MR AF-1a fusion protein. Purified AF-1a region-interacting proteins were found to contain RNA helicase A (RHA) and CBP. Further analysis showed that RHA interacted with the AF-1a region directly and then recruited a complex with histone acetyltransferase (HAT) activity that contained CBP. For full-length MR, aldosterone, but not hydrocortisone, was found to induce the binding of RHA/CBP complexes to the AF-1a region, as well as to allow the cooperative potentiation of MR transcriptional activity by RHA and CBP. In addition, a chromatin immunoprecipitation assay showed that aldosterone-bound MR, but not hydrocortisone-bound MR, recruited RHA/CBP complexes to native MR target gene promoters. Our results suggested that an altered conformation of the A/B region induced by aldosterone, but not hydrocortisone, might determine the accessibility of MR AF-1a to RHA/CBP complexes