MOLECULAR-CLONING OF A HIGHLY CONSERVED MOUSE AND HUMAN INTEGRAL MEMBRANE-PROTEIN (ITM1) AND GENETIC-MAPPING TO MOUSE CHROMOSOME-9

We have isolated and characterized a novel cDNA coding for a highly hy drophobic protein (B5) from a fetal mouse mandibular condyle cDNA libr ary, The full-length mouse B5 cDNA is 3095 nucleotides long and contai ns a potential open reading frame coding for a protein of 705 amino ac ids with a calculated molecular weight of 80.5 kDa, The B5 mRNA is dif ferentially polyadenylated, with the most abundant transcript having a length of 2.7 kb, The human homolog of B5 was isolated from a cDNA te stis library, The predicted amino acid sequence of the human B5 is 98. 5% identical to that of mouse, The most striking feature of the B5 pro tein is the presence of numerous (10-14) potential transmembrane domai ns, characteristic of an integral membrane protein, Similarity searche s in public databanks reveal that B5 is 58% similar to the T12A2,2 gen e of Caenorhabditis elegans and 60% similar to the STT3 gene of Saccha romyces cerevisiae, Furthermore, the report of an EST sequence (Access ion No, Z13858) related to the human B5, but identical to the STT3 gen e, indicates that B5 belongs to a larger gene family coding for novel putative transmembrane proteins, This family exhibits a remarkable deg ree of conservation in different species, The gene for B5, designated Itm1 (Integral membrane protein 1), is located on mouse chromosome 9. (C) 1996 Academic Press, Inc.