EXTL1

Gene Summary

Gene:EXTL1; exostosin-like glycosyltransferase 1
Aliases: EXTL
Location:1p36.1
Summary:This gene is a member of the multiple exostoses (EXT) family of glycosyltransferases, which function in the chain polymerization of heparan sulfate and heparin. The encoded protein harbors alpha 1,4- N-acetylglucosaminyltransferase activity, and is involved in chain elongation of heparan sulfate and possibly heparin. [provided by RefSeq, Jul 2008]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:exostosin-like 1
HPRD
Source:NCBIAccessed: 17 August, 2015

Ontology:

What does this gene/protein do?
Show (5)
Pathways:What pathways are this gene/protein implicaed in?
Show (2)

Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 17 August 2015 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • Neuroblastoma
  • DNA Mutational Analysis
  • Genes
  • Lymphocytes
  • Chromosome 8
  • Bacteriophage P1
  • Chromosome Deletion
  • Cartilage
  • N-Acetylglucosaminyltransferases
  • COS Cells
  • China
  • Family Health
  • DNA Sequence Analysis
  • Chromosome 1
  • Exons
  • Membrane Proteins
  • Proteins
  • Polymerase Chain Reaction
  • N-Acetylhexosaminyltransferases
  • Endoplasmic Reticulum
  • Sequence Homology
  • Hybrid Cells
  • Chromosome Mapping
  • Genetic Markers
  • Open Reading Frames
  • Tumor Suppressor Proteins
  • Missense Mutation
  • Young Adult
  • Exostoses, Multiple Hereditary
  • Cloning, Molecular
  • Breast Cancer
  • Expressed Sequence Tags
  • Molecular Sequence Data
  • Mutation
  • Physical Chromosome Mapping
  • Sex Factors
  • Multigene Family
  • Polymorphism
  • Northern Blotting
Tag cloud generated 17 August, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (3)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: EXTL1 (cancer-related)

Busse-Wicher M, Wicher KB, Kusche-Gullberg M
The exostosin family: proteins with many functions.
Matrix Biol. 2014; 35:25-33 [PubMed] Related Publications
Heparan sulfates are complex sulfated molecules found in abundance at cell surfaces and in the extracellular matrix. They bind to and influence the activity of a variety of molecules like growth factors, proteases and morphogens and are thus involved in various cell-cell and cell-matrix interactions. The mammalian EXT proteins have glycosyltransferase activities relevant for HS chain polymerization, however their exact role in this process is still confusing. In this review, we summarize current knowledge about the biochemical activities and some proposed functions of the members of the EXT protein family and their roles in human disease.

Mathysen D, Van Roy N, Van Hul W, et al.
Molecular analysis of the putative tumour-suppressor gene EXTL1 in neuroblastoma patients and cell lines.
Eur J Cancer. 2004; 40(8):1255-61 [PubMed] Related Publications
Although neuroblastoma is the most common extracranial solid tumour of childhood, little is known about its aetiology. Together with MYCN amplification and chromosome 17q gain, chromosome 1p deletion is one of the most frequently occurring genetic abnormalities in neuroblastoma. Based upon mapping of deletion breakpoints, putative tumour suppressor gene loci have been assigned to the distal part of the short arm of chromosome 1. Recently, the EXTL1 gene was suggested as a candidate neuroblastoma-suppressor gene and to evaluate this hypothesis, we performed 1p deletion analysis and mutation screening of the EXTL1-coding region on DNA from 22 primary neuroblastomas and 21 neuroblastoma cell lines. Deletions of the chromosome region 1p36.1, including the EXTL1 gene, were detected in several neuroblastoma cell lines and primary tumours. EXTL1 mutation screening resulted in the detection of one unclassified variant (Ser28Cys) but could not provide additional evidence of EXTL1 being involved in the aetiology of neuroblastoma.

Zak BM, Crawford BE, Esko JD
Hereditary multiple exostoses and heparan sulfate polymerization.
Biochim Biophys Acta. 2002; 1573(3):346-55 [PubMed] Related Publications
Hereditary multiple exostoses (HME, OMIM 133700, 133701) results from mutations in EXT1 and EXT2, genes encoding the copolymerase responsible for heparan sulfate (HS) biosynthesis. Members of this multigene family share the ability to transfer N-acetylglucosamine to a variety of oligosaccharide acceptors. EXT1 and EXT2 encode the copolymerase, whereas the roles of the other EXT family members (EXTL1, L2, and L3) are less clearly defined. Here, we provide an overview of HME, the EXT family of proteins, and possible models for the relationship of altered HS biosynthesis to the ectopic bone growth characteristic of the disease.

Stickens D, Brown D, Evans GA
EXT genes are differentially expressed in bone and cartilage during mouse embryogenesis.
Dev Dyn. 2000; 218(3):452-64 [PubMed] Related Publications
Hereditary multiple exostoses (HME) is a genetically heterogeneous disease characterized by the development of bony protuberances at the ends of all long bones. Genetic analyses have revealed HME to be a multigenic disorder linked to three loci on chromosomes 8q24 (EXT1), 11p11-13 (EXT2), and 19p (EXT3). The EXT1 and EXT2 genes have been cloned and defined as glycosyltransferases involved in the synthesis of heparan sulfate. EST database analysis has demonstrated additional gene family members, EXT-like genes (EXTL1, EXTL2, and EXTL3), not associated with a HME locus. The mouse homologs of EXT1 and EXT2 have also been cloned and shown to be 99% and 95% identical to their human counterparts, respectively. Here, we report the identification of the mouse EXTL1 gene and show it is 74% identical to the human EXTL1 gene. Expression studies of all three mouse EXT genes throughout various stages of embryonic development were carried out and whole-mount in situ hybridization in the developing limb buds showed high levels of expression of all three EXT genes. However, in situ hybridization of sectioned embryos revealed remarkable differences in expression profiles of EXT1, EXT2, and EXTL1. The identical expression patterns found for the EXT1 and EXT2 genes support the recent observation that both proteins form a glycosyltransferase complex. We suggest a model for exostoses formation based on the involvement of EXT1 and EXT2 in the Indian hedgehog/parathyroid hormone-related peptide (PTHrP) signaling pathway, an important regulator of the chondrocyte maturation process.

Spieker N, Beitsma M, van Sluis P, et al.
An integrated 5-Mb physical, genetic, and radiation hybrid map of a 1p36.1 region implicated in neuroblastoma pathogenesis.
Genes Chromosomes Cancer. 2000; 27(2):143-52 [PubMed] Related Publications
Common genetic aberrations of neuroblastoma are deletions of the short arm of chromosome 1 (1p36) and MYCN amplification. Our deletion analysis of 25 tumor cell lines and 171 tumors strongly suggests that 1p harbors several tumor suppressor loci. Distinct loci are involved in MYCN single-copy versus MYCN-amplified neuroblastoma. Deletions in MYCN single-copy tumors have a shortest region of overlap (SRO) of 20 cM at 1p36.3. MYCN-amplified tumors have large deletions with an SRO of about 60 cM, from 1p36.1 to the telomere. This SRO is defined by D1S7 (1p36.1), which was the most distal locus retained. Therefore, a suppressor gene associated with MYCN-amplified tumors probably maps within a few megabases distal of D1S7. In order to map this locus, we further refined this SRO. We mapped the breakpoint of the MYCN-amplified neuroblastoma with the smallest 1p deletion between 56.6 and 57.2 cM from 1pter. Pulsed-field gel electrophoresis and radiation hybrid mapping were used to construct a 5-Mb physical map of this region. The map includes the region from 82.73 till 92.89 cR from 1pter. About half of it was isolated in P1 and PAC clones. The region harbors the genes FGR, SLC9A1, HMG17, EXTL1, AML2, RH, OP18, four ESTs, and a newly identified gene with a transcript size of approximately 7 Kb. Several of the mapped genes have a putative role in cell growth, differentiation, and morphogenesis. Genes Chromosomes Cancer 27:143-152, 2000.

Wuyts W, Spieker N, Van Roy N, et al.
Refined physical mapping and genomic structure of the EXTL1 gene.
Cytogenet Cell Genet. 1999; 86(3-4):267-70 [PubMed] Related Publications
Recently, the EXTL1 gene, a member of the EXT tumor suppressor gene family, has been mapped to 1p36, a chromosome region which is frequently implicated in a wide variety of malignancies, including breast carcinoma, colorectal cancer and neuroblastoma. In this study, we show that the EXTL1 gene is located between the genetic markers D1S511 and D1S234 within 200 kb of the LAP18 gene on chromosome 1p36. 1, a region which has been proposed to harbor a tumor suppressor gene implicated in MYCN-amplified neuroblastomas. In addition, we determined the genomic structure of the EXTL1 gene, revealing that the EXTL1 coding sequence spans 11 exons within a 50-kb region.

Xu L, Xia J, Jiang H, et al.
Mutation analysis of hereditary multiple exostoses in the Chinese.
Hum Genet. 1999 Jul-Aug; 105(1-2):45-50 [PubMed] Related Publications
Hereditary multiple exostoses (EXT; MIM 133700) is an autosomal dominant bone disorder. It is genetically heterogeneous with at least three chromosomal loci: EXT1 on 8q24.1, EXT2 on 11p11, and EXT3 on 19p. EXT1 and EXT2, the two genes responsible for EXT1 and EXT2, respectively, have been cloned. Recently, three other members of the EXT gene family, named the EXT-like genes (EXTL: EXTL1, EXTL2, and EXTL3), have been isolated. EXT1, EXT2, and the three EXTLs are homologous with one another. We have identified the intron-exon boundaries of EXTL1 and EXTL3 and analyzed EXT1, EXT2, EXTL1, and EXTL3, in 36 Chinese families with EXT, to identify underlying disease-related mutations in the Chinese population. Of the 36 families, five and 12 family groups have mutations in EXT1 and EXT2, respectively. No disease-related mutation has been found in either EXTL1 or EXTL2, although one polymorphism has been detected in EXTL1. Of the 15 different mutations (three families share a common mutation in EXT2), 12 are novel. Most of the mutations are either frameshift or nonsense mutations (12/15). These mutations lead directly or indirectly to premature stop codons, and the mutations generate truncated proteins. This finding is consistent with the hypothesis that the development of EXT is mainly attributable to loss of gene function. Missense mutations are rare in our families, but these mutations may reflect some functionally crucial regions of these proteins. EXT1 is the most frequent single cause of EXT in the Caucasian population in Europe and North America. It accounts for about 40% of cases of EXT. Our study of 36 EXT Chinese families has found that EXT1 seems much less common in the Chinese population, although the frequency of the EXT2 mutation is similar in the Caucasian and Chinese populations. Our findings suggest a possibly different genetic spectrum of this disease in different populations.

Bièche I, Khodja A, Lidereau R
Deletion mapping of chromosomal region 1p32-pter in primary breast cancer.
Genes Chromosomes Cancer. 1999; 24(3):255-63 [PubMed] Related Publications
Distal alterations of the short arm of chromosome 1 are among the most frequent cytogenetic abnormalities in human breast carcinoma. We studied 96 primary human breast carcinomas for allelic imbalance using a panel of 31 polymorphic microsatellite, restriction fragment length polymorphism, and variable number of tandem repeat markers located mainly in the 1p32-pter region. Allelic imbalance at one or more loci was observed on the short arm of chromosome 1 in 56 (58.3%) of the 96 tumors. The 56 1p-altered tumor DNAs showed loss of heterozygosity (LOH), 12 (21.4%) at all informative loci tested and 44 (78.6%) at some loci. The LOH pattern of these 44 partially deleted tumors identified two distinct consensus regions of deletion on 1p32-pter (1p36.3 and 1p32). These regions match those described by other investigators but are considerably smaller. The 1p32 band is located within one of the two 1p regions of LOH in neuroblastoma, suggesting the involvement of the same unidentified tumor suppressor gene in both human breast cancer and neuroblastoma. The candidate tumor suppressor genes TNFR2, RIZ, DAN, RAP1GA1, FGR, MDGI, EXTL, and hRAD54 were excluded from the two consensus regions of deletion identified at 1p32-pter. Analysis of six polymorphic markers chosen to map within the other deleted regions described in breast tumors confirmed that two additional breast tumor suppressor genes are located in the proximal part (1p22 and 1p13) of chromosome arm 1p. Taken together, these results suggest that several unknown suppressor genes on 1p might be involved in the development of breast cancer. The refinement of the regions of LOH to within a few cM, and the recent publication of transcript maps of the human genome, mean that candidate genes and expressed sequence tags mapping to these deleted regions can now be investigated.

Van Hul W, Wuyts W, Hendrickx J, et al.
Identification of a third EXT-like gene (EXTL3) belonging to the EXT gene family.
Genomics. 1998; 47(2):230-7 [PubMed] Related Publications
Two homologous genes, EXT1 and EXT2, responsible for the development of benign multiple cartilagenous bone tumors (exostoses) on the long bones, have been identified in the past 2 years. Several arguments have been provided to support the hypothesis that these genes have tumor suppressor activity and that loss of function of these genes may contribute to the development of bone tumors. The recent identification of two EXT-like genes, EXTL1 and EXTL2, homologous to the EXT genes and to each other, revealed the existence of a larger family of genes. We now report the identification of a homologous EST (EST01365), not derived from the known EXT and EXTL genes, indicating the existence of one additional member of this gene family. We characterized this third EXT-like gene, EXTL3, and compared it with the other four members of the EXT-EXTL family. In view of its putative tumor suppressor function, the EXTL3 gene can be considered a candidate gene for the breast cancer locus on chromosome 8p12-p22.

Wuyts W, Van Hul W, Hendrickx J, et al.
Identification and characterization of a novel member of the EXT gene family, EXTL2.
Eur J Hum Genet. 1997 Nov-Dec; 5(6):382-9 [PubMed] Related Publications
Recently, two homologous genes, EXT1 and EXT2, with a putative tumor suppressor function have been described. Mutations in both genes are responsible for multiple exostosis syndrome (EXT), an autosomal dominant condition characterized by the presence of multiple osteochondromas, bony excrescences that sometimes undergo malignant transformation to chondrosarcoma. This family of EXT genes has been extended by the identification of an EXT-like (EXTL) gene showing a high degree of homology with the EXT genes. We report here a second EXT-like gene (EXTL2) which is homologous to the EXT and EXTL genes. EXTL2 consists of 5 exons encoding an ubiquitously expressed protein of 330 amino acids. In addition, a putative pseudogene, EXTL2P was also identified. The EXTL2 gene was assigned to chromosome 1p11-p12, whereas EXTL2P was mapped on chromosome 2q24-q31.

Wise CA, Clines GA, Massa H, et al.
Identification and localization of the gene for EXTL, a third member of the multiple exostoses gene family.
Genome Res. 1997; 7(1):10-6 [PubMed] Related Publications
Hereditary multiple exostoses (EXT) is an autosomal dominant disorder characterized by multiple bony outgrowths from the juxtaepiphyseal region of long bones. In a small proportion of cases, these exostoses progress to malignant chondrosarcomas. Genetic linkage of this disorder has been described to three independent loci on chromosomes 8q24.1 (EXT1), 11p11-13 (EXT2), and 19p (EXT-3). The EXT1 and EXT2 genes were isolated recently and show extensive sequence homology to each other. These genes are deleted in exostoses-derived tumors, supporting the hypothesis that they encode tumor suppressors. We have identified a third gene that shows striking sequence similarity to both EXT1 and EXT2 at the nucleotide and amino acid sequence levels, and have derived its entire coding sequence. Although the mRNA transcribed from this gene is similar in size to that from EXT1 and EXT2, its pattern of expression is quite different. We have localized this gene by fluorescence in situ hybridization to metaphase chromosomes and by whole genome radiation hybrid mapping to chromosome 1p36.1 between DIS458 and DIS511, region that frequently shows loss of heterozygosity in a variety of tumor types. This gene, EXTL (for EXT-like), is therefore a new member of the EXT gene family and is a potential candidate for several disease phenotypes.

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Cite this page: Cotterill SJ. EXTL1, Cancer Genetics Web: http://www.cancer-genetics.org/EXTL1.htm Accessed:

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