| *609709 | ||||||||
| GLYCOSYLTRANSFERASE-LIKE 1B; GYLTL1B | ||||||||
| Alternative titles; symbols | ||||||||
| LIKE-GLYCOSYLTRANSFERASE 2 LARGE2 | ||||||||
| HGNC Approved Gene Symbol: GYLTL1B | ||||||||
| Cytogenetic location: 11p11.2 Genomic coordinates (GRCh37): 11:45,943,195 - 45,950,646 (from NCBI) | ||||||||
| TEXT | ||||||||
| Cloning | ||||||||
| By database searching, Fujimura et al. (2005) identified a sequence, which they designated LARGE2, that showed homology to LARGE (603590), a putative glycosyltransferase thought to be involved in the maturation of alpha-dystroglycan (alpha-DG, DAG1; 128239). Fujimura et al. (2005) identified and subsequently cloned the LARGE2 gene from human kidney RNA. LARGE2 encodes a deduced 721-amino acid protein with a topology typical of a type II membrane protein, and a DXD motif that is present in many glycosyltransferases. The LARGE2 and LARGE proteins share 64.2% sequence identity. Quantitative real-time PCR showed that LARGE2 and LARGE are expressed almost ubiquitously. LARGE2 exhibits highest expression in placenta, followed by pancreas, mammary gland, and kidney. Unlike LARGE, which is expressed most highly in fetal brain, LARGE2 is hardly detectable in the central nervous system. | ||||||||
| Gene Function | ||||||||
| Fujimura et al. (2005) coexpressed alpha-DG with LARGE and LARGE2 in human embryonic kidney 3T3 cells and observed that LARGE2 supported the maturation of alpha-DG more effectively than LARGE and exerted its activity in addition to LARGE. Using deletion mutants of alpha-DG, Fujimura et al. (2005) found that LARGE and/or LARGE2 facilitate the functional glycosylation of the mucin-like domain of alpha-DG. In vitro pull-down assays indicated that LARGE2 recognizes the N-terminal domain of alpha-DG. Fujimura et al. (2005) suggested that LARGE and LARGE2 have compensatory functions that can explain the residual functionally glycosylated alpha-DG in a patient with a form of muscular dystrophy (MDC1D; 608840) who had null LARGE alleles. Brockington et al. (2005) showed that GYLTL1B and LARGE localized to the Golgi apparatus and both stimulated alpha-dystroglycan hyperglycosylation and increased its affinity for laminin binding. The authors suggested that GYLTL1B may be a candidate gene for muscular dystrophy, and that its overexpression could compensate for the deficiency of both LARGE and other glycosyltransferases. | ||||||||
| Mapping | ||||||||
| By sequence analysis, Fujimura et al. (2005) mapped the LARGE2 gene to chromosome 11p11.2. | ||||||||
| REFERENCES | ||||||||
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