Blood Group Antigen Gene Mutation Database

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Raph Blood Group System

Introduction

MER2 antigen defines the Raph blood group system. As shown recently by Crew et al. (Blood, 2003, 102, p4a) the antigen is located on CD151 glycoprotein which is a member of the four-transmembrane (TM4SF, tetraspanins) superfamily of proteins (show four conserved transmembrane domains). The protein was first characterized on platelet surface (GP27) but, has now been shown to have a wide tissue distribution and is also expressed on the surface of erythrocytes. It is an adhesion molecule.

The genes

The gene on chromosome 11p15.5 is organized in 8 exons and spans 4.3 kb; exons 2-8 encode the protein.

Function of proteins

Interacts with alpha-beta integrins and laminin participating in cell adhesion, proliferation and differentiation; may be involved in the structure and development of the glomerulus and the glomerular basement membrane in man. In cancer cells enhances cell motility, invasion and metastasis.

Tissue distribution

Expressed in many tissues including epithelium, endothelium, muscle, renal glomeruli and tubules, Schwann and dendritic cells; fibroblasts and other cell lines.

Disease association

Failure to express full lenght CD151 was shown to be associated in some individuals with glomeluralonephritis and renal failure (Crew et al., Blood, 2004 104 2217-2223).

About the alleles

The Raph blood group system is defined by a single antigen MER2, first recognized by a monoclonal antibody MER2. The antigen is expressed on erythrocytes of about 92% of Caucasians but the level of expression of MER2 varies among individuals; the remaining 8% of individuals are MER2 negative. Crew et al. (Blood, 2003, 102, p4a) identified CD151 as the protein that carries the MER2 antigen. Sequencing of CD151 gene in four MER2 negative individuals who produced alloanti-MER2, identified specific mutations, one of which, resulting in a frameshift and truncation of the protein, occurred in three patients with renal failure. In the list of alleles the sequence acc. no. BT007397 is taken as reference.

Other database IDs and links

Literature

New PubMed entries with the terms Raph and blood from the last 30 days.
NCBI Book Sections with the terms Raph and blood.

Contributors

Marion E. Reid, Immunohematology, New York Blood Center, 310 East 67 St., New York, N.Y., 10021

Olga O. Blumenfeld, Dept. of Biochemistry, Albert Einstein College of Medicine, New York, N.Y., 10461

Contributors for specific alleles are listed with the alleles.

Links