|Blood Group Antigen Gene Mutation Database|
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Yt Blood Group System
Gene locus - ACHE
The protein carrying the antigens for the Yt blood group system is acetylcholinesterase, the product of a single gene ACHE (previoualy YT). The gene is expressed in nervous and erythroid tissues, in different splicing forms; in the erythrocyte membrane the product is in the form of a glycosyl phosphadityl inositol (GPI)-linked glycoprotein. The gene is organized in six exons; exons 5 and 6 are alternatively spliced; exon 5 includes a 29 residue region that is present in the precursor form of the glycolipid-anchored acetylcholinesterase but is absent in the mature form. The GPI-anchor site coding region, is expressed in the erythroid tissues whereas the expression of exon 6 occurs in other tissues.
Function of proteins
Unknown in erythrocytes.
Erythroid and innervated tissues
Not clear; patients with paroxysmal nocturnal hemoglobinuria (PNH) have a population of complement-sensitive red cells (PNHIII) that lack all GPI-linked glycoproteins, including acetylcholinesterase. Human endplate acetylcholinesterase deficiency is caused by mutations in the ColQ gene; no mutations in ACHE have been found. The ColQ gene encodes the collagen-like tail that anchors acetylcholinesterase subunits to the basal lamina (Ohnoset al.).
So far, no variant phenotype associated with the YT blood group system has been observed. However, two alleles of ACHE were reported. Because differences in expression exist between erythroid and other tissues acetylcholinesterase, there is a problem in finding the appropriate reference sequence for the gene; reference acc. no. L42812 shows the sequence of the gene but seems to lack the region present in the precusor form of glycolipid-anchored acetylcholinesterase; also, navigating the numbering of nucleotides is quite difficult. Bartlets et al. publication is recommended for more details of the YTA/YTB changes (Am J Hum Genet. 1993 52: 928-936); reference acc. no M55040 is one of mRNA that shows this region but shows changes further downstream.
Other database IDs and links
Marion E. Reid and , Immunohematology, New York Blood Center, 310 East 67 St., New York, N.Y., 10021
, Genetics Dept., Case Western Reserve University, BRB / 747B, 2109 Adelbert Rd., Cleveland OH, 44106; Tel: 216 368-181
Contributors for specific alleles are listed with the alleles.
Updated 2008-12-17 21:38:20.890