Exon organization of the mouse entactin gene corresponds to the structural domains of the polypeptide and has regional homology to the low-density lipoprotein receptor gene.
Entactin is a widespread basement membrane protein of 150 kDa that binds to type IV collagen and laminin. The complete exon-intron structure of the mouse entactin gene has been determined from lambda genomic DNA clones. The gene spans at least 65 kb and contains 20 exons. The exon organization of the mouse entactin gene closely corresponds to the organization of the polypeptide into distinct structural and functional domains. The two amino-terminal globular domains are encoded by three exons each. Single exons encode the two protease-sensitive, O-glycosylated linking regions. The six EGF-like repeats and the single thyroglobulin-type repeat are each encoded by separate exons. The carboxyl-terminal half of entactin displays sequence homology to the growth factor-like region of the low-density lipoprotein receptor, and in both genes this region is encoded by eight exons. The positions of four introns are also conserved in the homologous region of the two genes. These observations suggest that the entactin gene has evolved via exon shuffling. Finally, several sequence polymorphisms useful for gene linkage analysis were found in the 3' noncoding region of the last exon.
Durkin
M E
ME
Department of Biological Sciences, University of Pittsburgh, Pennsylvania 15260, USA.
Wewer
U M
UM
Chung
A E
AE
D000595:Amino Acid Sequence; D000818:Animals; D016384:Consensus Sequence; D005091:Exons / Q000235:genetics*; D005796:Genes; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics*; D051379:Mice / Q000235:genetics*; D008806:Mice, Inbred AKR; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D011973:Receptors, LDL / Q000235:genetics*; D017386:Sequence Homology, Amino Acid
D008562:Membrane Glycoproteins; D011973:Receptors, LDL; C029967:nidogen