Identification and characterization of a cDNA and the structural gene encoding the mouse epithelial membrane protein-1.
The PMP22/EMP/MP20 gene family includes four closely related proteins, peripheral myelin protein-22 (PMP22), epithelial membrane protein-1 (EMP-1), epithelial membrane protein-2 (EMP-2), and epithelial membrane protein-3 (EMP-3), which share amino acid identities ranging from 33 to 43%. In addition, the lens-specific membrane protein MP20 represents a more distant relative. Functionally, this family of proteins is likely to play important roles in the control of cell proliferation, cell differentiation, and cell death. In particular, mutations affecting the PMP22 gene are responsible for various hereditary peripheral neuropathies in humans and mice. We report the isolation and characterization of a mouse EMP-1 cDNA and the corresponding emp-1 gene. Mouse EMP-1 displays 93% amino acid identity to rat EMP-1 and 39% identity to mouse PMP22. The cDNA-predicted EMP-1 protein contains four putative membrane-associated domains and can be N-linked glycosylated in vitro. EMP-1 is encoded by a single-copy gene with the positions of introns exactly conserved between emp-1 and PMP22, corroborating the hypothesis that both genes belong to the same family. Computer-predicted structural domains of EMP-1 are partially mirrored by the exon/intron structure of emp-1. Most interestingly, exon 4, which covers the potential second transmembrane domain, a small intracellular loop, and half of the third transmembrane domain, encodes the most highly conserved regions between the EMP-1 and PMP22 proteins and is also remarkably conserved in the MP20 gene, indicating some shared functional significance for this module in the PMP22/EMP/MP20 family.
Lobsiger
C S
CS
Department of Biology, Swiss Federal Institute of Technology, Zurich, Switzerland.
Magyar
J P
JP
Taylor
V
V
Wulf
P
P
Welcher
A A
AA
Program
A E
AE
Suter
U
U
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary; D005136:Eye Proteins / Q000235:genetics; D006801:Humans; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D009185:Myelin Proteins / Q000235:genetics; D009363:Neoplasm Proteins; D011110:Polymorphism, Genetic; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics; D011956:Receptors, Cell Surface; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
D018076:DNA, Complementary; D005136:Eye Proteins; C044539:LIM2 protein, human; C489025:Lim2 protein, mouse; C489026:Lim2 protein, rat; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009185:Myelin Proteins; D009363:Neoplasm Proteins; C073687:PMP22 protein, human; C489545:Pmp22 protein, mouse; C489546:Pmp22 protein, rat; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; C097051:epithelial membrane protein-1