Literature summary for 2.4.2.38 extracted from

Klutts, J.S.; Doering, T.L.
Cryptococcal xylosyltransferase 1 (Cxt1p) from Cryptococcus neoformans plays a direct role in the synthesis of capsule polysaccharides (2008), J. Biol. Chem., 283, 14327-14334.

Application

Application	Comment	Organism
medicine	xylose residues within the capsule polysaccharide are important for normal host-pathogen interaction, loss of CXT1p attenuates virulence	Cryptococcus neoformans
medicine	loss of XT1 leads to attenuation of virulence	Cryptococcus neoformans

Cloned(Commentary)

Cloned (Comment)	Organism
5-kb PCR product cloned into the TOPO pCR2.1 vector and maintained in Escherichia coli DH5alpha	Cryptococcus neoformans
amplification of the gene with flanking regions (1.3 kb upstream of the start codon, 1 kb downstream of the gene) from serotype D (strain JEC21) genomic DNA for cloning in pCR2.1TOPO, generation of replacement cassettes for replacing endogenous CXT1p: (i) nourseothricin acetyltransferase resistance gene flanked by the CXT1p flanking regions, transformed as linear DNA in CAP67 strain, (ii) cxt1 gene lacking 3 two-thirds of the encoding sequence flanked by its flanking regions, transformed as linear DNA in JEC21 strain	Cryptococcus neoformans

Cloned (Comment)

Organism

5-kb PCR product cloned into the TOPO pCR2.1 vector and maintained in Escherichia coli DH5alpha

Cryptococcus neoformans

amplification of the gene with flanking regions (1.3 kb upstream of the start codon, 1 kb downstream of the gene) from serotype D (strain JEC21) genomic DNA for cloning in pCR2.1TOPO, generation of replacement cassettes for replacing endogenous CXT1p: (i) nourseothricin acetyltransferase resistance gene flanked by the CXT1p flanking regions, transformed as linear DNA in CAP67 strain, (ii) cxt1 gene lacking 3 two-thirds of the encoding sequence flanked by its flanking regions, transformed as linear DNA in JEC21 strain

Cryptococcus neoformans

Localization

Localization	Comment	Organism	GeneOntology No.	Textmining

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.	Reac.
UDP-D-xylose + galactoxylomannan	Cryptococcus neoformans	-	UDP + [beta-D-xylose-(1,2)]-galactoxylomannan	JEC21/cxt1delta and CAP67/cxt1delta lacking CXT1p: almost complete loss of beta-xylose residues (1,2)-linked to mannose, unchanged amounts of beta-xylose (1,3)-linked to galactose	?
UDP-D-xylose + glucuronoxylomannan	Cryptococcus neoformans	-	UDP + [beta-D-xylose-(1,2)]-glucuronoxylomannan	JEC21/cxt1delta and CAP67/cxt1delta lacking CXT1p: 30% decrease in amount of xylose, 39% decrease in O-2 xylose-substituted mannose, 31.5% increase in O-2-unsubstituted mannose, loss of 1/3 of beta-(1,2)-linked xylose, revealed by NMR analyses	?

Organism

Organism	UniProt	Comment	Textmining
Cryptococcus neoformans	-	wild-type strain JEC20 (serotype D MAT a), wild-type strain JEC21 (serotype D MAT alpha), mutant strain CAP67 (serotype D MAT alpha cap59), mutant strain JEC21/cxt1delta (serotype D, isogenic MAT alpha, encapsulated and nourseothricin-resistant, lacking CXT1p), mutant strain CAP67/cxt1delta (serotype D, isogenic MAT alpha, acapsulated and nourseothricin-resistant, lacking CXT1p)	-
Cryptococcus neoformans	Q5K8R6	strains JEC20, JEC21 and CAP67	-

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.
additional information	lack of CXT1p in membranes from JEC21/cxt1delta and CAP67/cxt1delta leads to dramatic reduction in D-xylose-beta-(1,2)-D-mannose-alpha-(1,3)-D-mannose synthesising activity in presence of exogenously added substrate	Cryptococcus neoformans	?	-	?
UDP-D-xylose + D-mannosyl-alpha-(1,3)-D-mannose	membranes, radiolabelled UDP-xylose, alpha-(1,3)-mannobiose (resembles backbone or dimannose moiety of natural substrates)	Cryptococcus neoformans	UDP + D-xylosyl-beta-(1,2)-D-mannosyl-alpha-(1,3)-D-mannose	product: trisaccharide with xylose moiety linked to reducing mannose of alpha-(1,3)-mannobiose, radiolabel detection by scintillation counting or thin layer chromatography and autoradiography, product purification for NMR and glycosyl linkage analyses	?
UDP-D-xylose + galactoxylomannan	-	Cryptococcus neoformans	UDP + [beta-D-xylose-(1,2)]-galactoxylomannan	JEC21/cxt1delta and CAP67/cxt1delta lacking CXT1p: almost complete loss of beta-xylose residues (1,2)-linked to mannose, unchanged amounts of beta-xylose (1,3)-linked to galactose	?
UDP-D-xylose + glucuronoxylomannan	-	Cryptococcus neoformans	UDP + [beta-D-xylose-(1,2)]-glucuronoxylomannan	JEC21/cxt1delta and CAP67/cxt1delta lacking CXT1p: 30% decrease in amount of xylose, 39% decrease in O-2 xylose-substituted mannose, 31.5% increase in O-2-unsubstituted mannose, loss of 1/3 of beta-(1,2)-linked xylose, revealed by NMR analyses	?

Synonyms

Synonyms	Comment	Organism
beta-1,2-xylosyltransferase	-	Cryptococcus neoformans
beta1,2-xylosyltransferase	-	Cryptococcus neoformans
Cryptococcal xylosyltransferase	-	Cryptococcus neoformans
Cxt1p	-	Cryptococcus neoformans
XT1	-	Cryptococcus neoformans
Xt1p	-	Cryptococcus neoformans
xylosyltransferase I	-	Cryptococcus neoformans

General Information

General Information	Comment	Organism
malfunction	loss of XT1 does not affect in vitro growth of mutant cells or general morphology of their capsules. The two main capsule polysaccharides, glucuronoxylomannan and galactoxylomannan, both are missing beta1,2-xylose residues. Deletion of XT1 leads to attenuation of cryptococcal growth in a mouse model of infection	Cryptococcus neoformans
physiological function	Xt1p has a defined role in capsule biosynthesis	Cryptococcus neoformans