UGT1A1

UDP glucuronosyltransferase 1 family, polypeptide A1
Identifiers
Symbol(s)	UGT1A1; UGT1; GNT1; UGT1A; UDPGT; HUG-BR1; UGT1*1
External IDs	OMIM: 191740 MGI: 98898 Homologene: 83117
Gene Ontology Molecular Function: • glucuronosyltransferase activity Cellular Component: • endoplasmic reticulum • microsome • membrane • integral to membrane Biological Process: • bilirubin conjugation • digestion • metabolic process • estrogen metabolic process
Orthologs
	Human	Mouse
Entrez	54658	394436 Additional recommended knowledge Don't let static charges disrupt your weighing accuracy Safe Weighing Range Ensures Accurate Results What is the Correct Way to Check Repeatability in Balances?
Refseq	NM_000463 (mRNA) NP_000454 (protein)	NM_201645 (mRNA) NP_964007 (protein)
Pubmed search	[1]	[2]

This gene encodes a UDP-glucuronosyltransferase, an enzyme of the glucuronidation pathway that transforms small lipophilic molecules, such as steroids, bilirubin, hormones, and drugs, into water-soluble, excretable metabolites. This gene is part of a complex locus that encodes several UDP-glucuronosyltransferases. The locus includes thirteen unique alternate first exons followed by four common exons. Four of the alternate first exons are considered pseudogenes. Each of the remaining nine 5' exons may be spliced to the four common exons, resulting in nine proteins with different N-termini and identical C-termini. Each first exon encodes the substrate binding site, and is regulated by its own promoter. The preferred substrate of this enzyme is bilirubin, although it also has moderate activity with simple phenols, flavones, and C18 steroids. Mutations in this gene result in Crigler-Najjar syndromes types I and II and in Gilbert syndrome.^[1]

UGT1A1 is a gene associated with Crigler-Najjar syndrome, and a common splice variant is associated with serious side effects to the common chemotherapeutic drug irinotecan. The primary function of the gene's protein product is uridine diphospate glycosyltrasnferase 1 and is involved in the conversion of lipophilic molocules to water soluble substances suitable for excretion via substrate glycosylation.

Lack of expression of UGT1A1 in the neonatal liver is the major cause of jaundice in newborns. This jaundice is generally caused by massive breakdown of fetal blood cells which produces bilirubin which cannot be cleared if UGT1A1 is expressed at low levels or is absent. This type of jaundice can remedied by UV light exposure.

It transports bilirubin and phenol.

See also

• Glucuronosyltransferase

References

Further reading