ABO (gene)

ABO blood group (transferase A, alpha 1-3-N-acetylgalactosaminyltransferase; transferase B, alpha 1-3-galactosyltransferase)
250px PDB rendering based on 1lz0.
Available structures PDB Ortholog search: PDBe, RCSB List of PDB id codes 1LZ0, 1LZ7, 1LZI, 1LZJ, 1R7T, 1R7U, 1R7V, 1R7X, 1R7Y, 1R80, 1R81, 1R82, 1WSZ, 1WT0, 1WT1, 1WT2, 1WT3, 1XZ6, 1ZHJ, 1ZI1, 1ZI3, 1ZI4, 1ZI5, 1ZIZ, 1ZJ0, 1ZJ1, 1ZJ2, 1ZJ3, 1ZJO, 1ZJP, 2A8U, 2A8W, 2I7B, 2O1F, 2O1G, 2O1H, 2PGV, 2PGY, 2RIT, 2RIX, 2RIY, 2RIZ, 2RJ0, 2RJ1, 2RJ4, 2RJ5, 2RJ6, 2RJ7, 2RJ8, 2RJ9, 2Y7A, 3I0C, 3I0D, 3I0E, 3I0F, 3I0G, 3I0H, 3I0I, 3I0J, 3I0K, 3I0L, 3IOH, 3IOI, 3IOJ, 3SX3, 3SX5, 3SX7, 3SX8, 3SXA, 3SXB, 3SXC, 3SXD, 3SXE, 3SXG, 3U0X, 3U0Y, 3V0L, 3V0M, 3V0N, 3V0O, 3V0P, 3V0Q, 3ZGF, 3ZGG, 4C2S, 4FQW, 4FRA, 4FRB, 4FRD, 4FRE, 4FRH, 4FRL, 4FRM, 4FRO, 4FRP, 4FRQ, 4GBP, 4KC1, 4KC2, 4KC4, 4KXO
Identifiers
Symbols	ABO ; A3GALNT; A3GALT1; GTB; NAGAT
External IDs	OMIM: 110300 MGI: 2135738 HomoloGene: 69306 GeneCards: ABO Gene
EC number	2.4.1.37, 2.4.1.40
Gene ontology Molecular function • glycoprotein-fucosylgalactoside alpha-N-acetylgalactosaminyltransferase activity • fucosylgalactoside 3-alpha-galactosyltransferase activity • metal ion binding Cellular component • extracellular region • integral component of membrane • Golgi cisterna membrane Biological process • protein glycosylation Sources: Amigo / QuickGO
RNA expression pattern
File:PBB GE ABO 214504 at tn.png
File:PBB GE ABO 216929 x at tn.png
More reference expression data
Orthologs
Species	Human	Mouse
Entrez	28	80908
Ensembl	ENSG00000175164	ENSMUSG00000015787
UniProt	P16442	P38649
RefSeq (mRNA)	NM_020469	NM_001290444
RefSeq (protein)	NP_065202	NP_001277373
Location (UCSC)	Chr 9: 133.25 – 133.28 Mb	Chr 2: 26.84 – 26.86 Mb
PubMed search	[1]	[2]

Histo-blood group ABO system transferase is an enzyme with glycosyltransferase activity which in humans is encoded by the ABO gene.

It determines the ABO blood group of an individual by modifying the oligosaccharides on cell surface glycoproteins. Variations in the sequence of the protein between individuals determine the type of modification and the blood group.

Function

This gene encodes a protein related to the first discovered blood group system, ABO. Which allele is present in an individual determines the blood group. The 'O' blood group is caused by a deletion of guanine-258 in the gene which corresponds to a region near the N-terminus of the protein. This results in a frameshift and translation of an almost entirely different protein. This mutation results in a protein unable to modify oligosaccharides which end in fucose linked to galactose. This sugar combination is termed the H antigen.

The A and B alleles of the ABO gene express enzymes with glycosyltransferase activities that differ, adding either N-acetyl galactosamine or galactose to the H antigen, converting it into the A or B antigen respectively. Individuals who are heterozygous for this gene express both proteins and so make both A and B antigens. Their blood group is AB. Remarkably, the difference between the A and B glycosyltransferase enzymes is only four amino acids. Other minor alleles have been found for this gene.

Common alleles

Further information: ABO blood group system § Distribution and evolutionary history

There are six common alleles in individuals of European descent the ABO gene that produce one's blood type:

• A
  • A101 (A1)
  • A201 (A2)
• B
  • B101 (B1)
• O
  • O01 (O1)
  • O02 (O1v)
  • O03 (O2)

Many rare variants of these alleles have been found in human populations around the world.

Clinical signficance

A genome-wide association study has identified variants in the ABO locus associated with susceptibility to pancreatic cancer.

Further reading

This article incorporates text from the United States National Library of Medicine, which is in the public domain.