title: Localization of a human homolog of the mouse Tiam-1 gene to chromosome 21q22.1.
abstract: Exon trapping was applied to genomic DNA from a chromosome 21-specific cosmid library (LL21NC02-Q) to clone portions of genes from this chromosome. Among a large number of trapped exons, three showed striking homology to different regions of the cDNA for the mouse T-lymphoma invasion and metastasis gene (Tiam-1) at both nucleotide and predicted amino acid sequence levels, suggesting that these three exons are part of a human homolog of the mouse Tiam-1 gene. We mapped this presumed human TIAM1 gene to chromosome 21 by using appropriate somatic cell hybrids, YACs, and cosmids. The TIAM1 gene localizes to YAC 760H5 of the I. Chumakov et al. (1992, Nature 359: 380) YAC contig between markers D21S298 and D21S404 in band 21q22.1. This human gene (which is a member of the group of guanine nucleotide-dissociation stimulators that modulate the activity of Rho-like proteins) may be important in the development or metastasis of malignancies that are associated with abnormalities on chromosome 21, including the various forms of leukemia frequent in trisomy 21.
authors.affiliation: Department of Genetics and Microbiology, University of Geneva Medical School, Switzerland.
authors.forename: H
authors.initials: H
authors.lastname: Chen
authors.forename: S E
authors.initials: SE
authors.lastname: Antonarakis
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018244:Chromosomes, Artificial, Yeast; D002891:Chromosomes, Human, Pair 21; D004314:Down Syndrome / Q000235:genetics; D020662:Guanine Nucleotide Exchange Factors; D006801:Humans; D006822:Hybrid Cells; D051379:Mice; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction / Q000379:methods; D011506:Proteins / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D000075684:T-Lymphoma Invasion and Metastasis-inducing Protein 1
chemical_list: D020662:Guanine Nucleotide Exchange Factors; D011506:Proteins; D000075684:T-Lymphoma Invasion and Metastasis-inducing Protein 1; C087334:TIAM1 protein, human; C513260:Tiam1 protein, mouse