The avian vitamin D receptors: primary structures and their origins.

Abstract

ABSTRACTcDNA cones ening Japanese quidl chorioallantoic membrane and chicken kidney 1,25-dihydroyvitamin D3 receptors were isolated and the total 448-amino acid (aa) sequence was deduced. (7). Another report from the same group (9), based on in vitro translation, suggested that the VDR protein is not synthesized as a large (>>60 kDa) parent molecule that is subsequently processed into a smaller protein. They concluded that the presence of the lower molecular mass protein could be a translation product of multiple transcripts, as is the case for glucocorticoid receptors or represents post-translationally modified species (9). Pike et al. (7) showed that both A and B forms ofcVDR bind similarly to DNA and, thus, are not analogous in properties to the A and B polypeptides of the avian progesterone receptor (10). The considerable debate over the origin of the B form of the avian VDR and the suggestion that this 58-kDa form may arise by proteolysis of the larger A form receptor protein led us to isolate the full-length cDNA encoding the avian VDRs.*We present evidence to demonstrate that the A and B forms of the avian VDR are derived by alternate initiation of translation from two in-phase ATG initiation signals located on a single mRNA transcript.MATERIALS AND METHODS Identification Of Japanese Quail (q) VDR cDNAs. An oligo(dT)-primed and random-primed Agtll cDNA library made from 5 pug of jqCAM poly(A)+ mRNA was screened using 358-and 1783-bp fragments from the coding region of the rVDR (3). For the first round of screening, recombinant phages were plated at a density of 15,000 plaque-forming units per 150-mm plate on a lawn of Escherichia coli y1090. Lifted Hybond-N nylon filters were prehybridized for 12 h at 420C in 50%o (vol/vol) formamide/Sx SSPE/5x Denhardt's solution/0.1% SDS containing denatured salmon sperm DNA (100 pg/ml) (lx SSPE = 0.18 M NaCl/10 mM sodium phosphate, pH 7.4/1 mM EDTA). Nick-translated probe was added to the-filters (1 x 106 cpm) (11). After hybridization for 30 h at 420C, the filters were washed successively in 2x SSC/0.1% SDS at room temperature for 15 min, lx SSC/ 0.1% SDS at 650C for 1 h, and finally, if necessary, in 0.1x SSC/0.1% SDS at 650C for 1 h. Filters were then exposed to

Vitamin D Receptor Gene Haplotype Is Associated with Late-Onset Alzheimer's Disease

“…mone in tissues, which are not primarily related to mineral metabolism, have been shown within last 30 years. Vitamin D is suggested to act as a neuroactive steroid due to the local bioactivation of the pre-vitamin D hormone in the central nervous system (CNS) and the widely distributed localization of nuclear receptor throughout the brain (Luine et al 1987;Musiol et al 1992;Elaroussi et al 1994;Johnson et al 1996;Veenstra et al 1998;Prufer et al 1999;Miller and Portale 2000;Langub et al 2001;Garcion et al 2002;Burkert et al 2003;Eyles et al 2005;McCann and Ames. 2008;Cekic et al 2009;Dickens et al 2011).…”

Vitamin D: calcium and bone homeostasis during evolution

“…74 This has also been clearly confirmed in reptiles such as lizards. 75 Vitamin D deficiency in birds (for example, chick or gallus domesticus), and quail 76 creates a dual problem as vitamin D is essential for calcium absorption and bone mineralization but also essential for egg shell calcification. Indeed, in animals laying hard-shelled eggs, there is a need for rapid calcium supply to the uterus for deposition of calcium.…”

Multiple promoters direct the tissue-specific expression of novel N-terminal variant human vitamin D receptor gene transcripts

“…1B) utilizes exon 1d in place of exon 1a of the hVDR cDNA. Three minor variants (7,8, and 9 in Fig. 1B) arise from alternative splicing of exons 1b and 1c into or out of the transcript, analogous to the exon 1a-containing variants 2, 3, and 4.…”