Genomic organization and chromosomal localization of the Itm2a gene

Abstract

Itm2A is a novel type II integral membrane protein that is involved in osteo- and chondrogenic differentiation. Itm2a cDNA was originally isolated from a cDNA library of organ cultures from prenatal mouse mandibular condyles, by subtractive hybridization and differential screening. The Itm2a gene was isolated from a BALB/c liver genomic library. In total, 9.4 kb of the gene were sequenced, of which 2649 bp are 5' flanking sequences. The Itm2a gene contains six exons and five introns. The splice sites conform to the GT/AG rule. The 5' flanking region, which contains the presumed promoter sequence, lacks the common TATAA and CCAAT sequences, but contains consensus binding sites for various transcription factors. Several of these transcription factors are known to play a role in transcriptional regulation of cartilage- or bone-specific genes (e.g. Cbfa1, Cart-1, MHox, HES-1, and CIIS1). Itm2a was mapped to mouse chromosome position XA2-XA3 by fluorescent in situ hybridization (FISH) analysis. The human homolog, ITM2A, was mapped to chromosome position Xq13.3-Xq21.2.

Rat Blood–Brain Barrier Genomics. II

“…The amyloid plaque of familial Danish dementia is formed by a 4-KD peptide designated Adan. The Adan peptide is produced by a point mutation in the BRI gene, which encodes a transmembrane type II protein that is also called the Itm2b protein (Vidal et al, 2000), which has a 39% amino acid identity with the human Itm2a membrane protein (Pittois et al, 1999). Clone LKH-24 is the rat homologue of mouse Itm2a, which is differentially expressed at the brain microvasculature in both the rat (Table 1) and in humans (Shusta et al, 2002a).…”

Chromosome 13 dementias

“…The genomic organization in both human and mouse consists of six exons and five introns. The first intron is remarkably longer in comparison with the other four and may contain regulatory sequences [6,8]. Each of the family members was mapped to a different chromosome by fluorescence in situ hybridization: the human BRI1 gene is located in chromosome X [8], BRI2 in the long arm of chromosome 13 [5] and BRI3 in chromosome 2 [6].…”

Itm2a Expression in the Developing Mouse First Lower Molar, and the Subcellular Localization of Itm2a in Mouse Dental Epithelial Cells

“…These Itm2 proteins consist of four regions with distinct properties; the hydrophobic, linker, BRICHOS and C-terminal regions, as do other proteins in the BRICHOS superfamily [19], and are type II transmembrane proteins. Itm2a bears one BRICHOS domain at the C-terminal extracellular side [20], [21]. The expression of Itm2c is restricted to the brain [22], whereas Itm2b is ubiquitously expressed [23].…”