The rat vitamin‐D‐dependent calcium‐binding protein (9‐kDa CaBP) gene

Abstract

The structural organization of the entire rat vitamin-D-dependent calcium-binding protein (9-kDa CaBP) gene was determined by analysis of overlapping genomic clones isolated from a rat genomic library using the rat 9-kDa CaBP cDNA [Desplan C., Heidmann O., Lillie J., Auffray C. and Thomasset M. (1983) J. Biol. Chem. 258, 13502-13505]. These clones together span 30 kbp of rat genomic DNA, with the rat 9-kDa CaBP gene lying in the middle. The 9-kDa CaBP gene is 2.5 kbp long and contains three exons interrupted by two introns. The first exon contains almost the entire 5' untranslated region. The second exon codes for the calcium-binding site I, the third exon codes for site II and the 3' untranslated region. Therefore each of the calcium-binding domains is encoded by single, separate exons. The transcription initiation site was identified by S1 nuclease mapping and primer extension. A consensus sequence TATAAA is localized 31 bp upstream from the cap site and the 'CCAAT-box' lies upstream from the transcription start. Single (AC)25 and (AG)23 repeats are present in the second intron together with an Alu-like sequence. Repetitive elements are present 5 kbp upstream from the cap site and in the 3' flanking region. Comparison of the known rat CaBP sequences (9-kDa CaBP, 28-kDa CaBP, S100 protein) shows that the 9-kDa CaBP is more closely related to the S100 protein than to the 28-kDa CaBP. There is no evidence to indicate that 9-kDa CaBP has arisen from the 28-kDa CaBP.

Identification of a 1,25-dihydroxyvitamin D3-response element in the 5'-flanking region of the rat calbindin D-9k gene.

“…The rat gene for calbindin D-9k has also been isolated and sequenced (20,21). It is a relatively small gene, spanning about three kilobases (kb) of genomic DNA, and consists of three exons flanked by two introns (20,21).In the intestine, vitamin D appears to be the primary regulator for the calbindin D-9k gene at the transcriptional level (22-25). However, no regulation by vitamin D is exerted on the gene in the uterus, where it seems to be primarily under estrogen regulation (7,26).…”

“…The rat calbindin D-9k cDNA has been isolated and characterized (19). The rat gene for calbindin D-9k has also been isolated and sequenced (20,21). It is a relatively small gene, spanning about three kilobases (kb) of genomic DNA, and consists of three exons flanked by two introns (20,21).…”

Estradiol-dependent uterine leiomyomas in transgenic mice.

“…We have targeted the expression of the early region of simian virus 40 (SV40) 1 large tumor antigen (Tag) to the uterine myometrium of transgenic mouse using the 5 Ј flanking regions of the rat Calbindin D-9K (CaBP9K) gene (13). CaBP9K is found in several rat tissues, such as enterocytes, myometrium, and epithelial alveolar cells of the lung (14)(15)(16)(17).The uterine CaBP9K gene is under the positive control of estradiol; the gene is silent in ovariectomized rodents (18,19) and strongly activated after estradiol treatment (20,21).…”

Transcriptional Regulation of Rat Calbindin Expression during Development Determined by Bacterially Expressed Protein.

“…It has a molecular weight of 9,000 and its expression depends on the level of 1, 25-dihydroxyvitamin D3 (1,2). The nucleotide sequence (3,4) and amino acid sequence of calbindin-D9k (5) have already been determined. However, the mo lecular mechanism of its exact function in intestinal mucosal cells and how its * To whom correspondence should be addressed .…”

“…Although Brehier and Thomasset (25) showed the increased expression of calbindin-D9k as the result of high-calcium content in an organ culture of fetus tissue, the mechanism of response against the concentration of calcium may be different between fetal and adult tissues. Both the rat calbindin-D9k cDNA (24) and gene (3,4) have been characterized. …”