title: Phylogenetic origin of LI-cadherin revealed by protein and gene structure analysis.
abstract: The intestine specific LI-cadherin differs in its overall structure from classical and desmosomal cadherins by the presence of seven instead of five cadherin repeats and a short cytoplasmic domain. Despite the low sequence similarity, a comparative protein structure analysis revealed that LI-cadherin may have originated from a five-repeat predecessor cadherin by a duplication of the first two aminoterminal repeats. To test this hypothesis, we cloned the murine LI-cadherin gene and compared its structure to that of other cadherins. The intron-exon organization, including the intron positions and phases, is perfectly conserved between repeats 3-7 of LI-cadherin and 1-5 of classical cadherins. Moreover, the genomic structure of the repeats 1-2 and 3-4 is identical for LI-cadherin and highly similar to that of the repeats 1-2 of classical cadherins. These findings strengthen our assumption that LI-cadherin originated from an ancestral cadherin with five domains by a partial gene duplication event.
authors.affiliation: Institute of Laboratory Medicine and Biochemistry, Virchow-Hospital of Charité Medical School, Humboldt University of Berlin, Augustenburger Platz 1, 13353 Berlin, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Jung
authors.forename: M W
authors.initials: MW
authors.lastname: Wendeler
authors.forename: M
authors.initials: M
authors.lastname: Danevad
authors.forename: H
authors.initials: H
authors.lastname: Himmelbauer
authors.forename: R
authors.initials: R
authors.lastname: Gessner
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D015820:Cadherins / Q000737:chemistry; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics*; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000378:metabolism; D017931:DNA Primers / Q000737:chemistry; D018076:DNA, Complementary / Q000378:metabolism; D005091:Exons; D007413:Intestinal Mucosa / Q000378:metabolism; D007438:Introns; D026901:Membrane Transport Proteins; D051379:Mice; D008969:Molecular Sequence Data; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D051381:Rats; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
chemical_list: D015820:Cadherins; D002352:Carrier Proteins; C490585:Cdh17 protein, mouse; C490586:Cdh17 protein, rat; D017931:DNA Primers; D018076:DNA, Complementary; D026901:Membrane Transport Proteins; C067802:intestinal peptide-proton cotransporter