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D Stickens

Publications and source records attributed to D Stickens.

7 recordsLinked to original sources
PubMed2000

EXT genes are differentially expressed in bone and cartilage during mouse embryogenesis.

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.

Amino Acid Sequence↗
PubMed1997

Isolation and characterization of the murine homolog of the human EXT2 multiple exostoses gene.

Multiple exostoses is a polygenic disease of bone formation and development characterized by the presence of cartilage-capped osseous projections emanating from the end of the long bones. Two members of a recently defined multigene family of proteins (EXT1 and 2) were shown to be involved in this disease. To investigate the evolutionary relatedness of EXT genes across species we isolated the mouse EXT2 cDNA. As in the human counterpart, the mouse EXT2 cDNA contains an open reading frame of 2154 bp encoding a predicted protein of 718 amino acids. The nucleic acid sequence is 87% identical to the human EXT2 transcript, resulting in an amino acid sequence which is 95% identical to the human protein. The mouse EXT2 gene also shows significant sequence similarity to the mouse and human EXT1 gene. Northern blot analysis shows that this gene is expressed in early stages of embryonic development, and in situ hybridizations suggest that EXT2 plays a role in limb development. The identification of the mouse EXT2 gene will allow functional analysis through insertional inactivation and reverse genetics in mice in order to better understand the formation of exostoses during bone formation.

Amino Acid Sequence↗
PubMed1996

The EXT2 multiple exostoses gene defines a family of putative tumour suppressor genes.

Hereditary multiple exostoses (EXT) is an autosomal dominant condition characterized by short stature and the development of bony protuberances at the ends of all the long bones. Three genetic locl have been identified by genetic linkage analysis at chromosomes 8q24.1, 11p11-13 and 19p. The EXT1 gene on chromosome 8 was recently identified and characterized. Here, we report the isolation and characterization of the EXT2 gene. This gene shows striking sequence similarity to the EXT1 gene, and we have identified a four base deletion segregating with the phenotype. Both EXT1 and EXT2 show significant homology with one additional expressed sequence tag, defining a new multigene family of proteins with potential tumour suppressor activity.

Amino Acid Sequence↗
PubMed1995

Characterization of a processed pseudogene of human FAU1 on chromosome 18.

A member of the human FAU (Finkel-Biskis-Reilly murine sarcoma virus-associated ubiquitously expressed) gene subfamily, encoding the ribosomal protein S30 fused in frame to an ubiquitin-like protein, was cloned, sequenced and analysed. This clone, FAU1P, is a processed pseudogene with a completely intact, although transcriptionally silent, open reading frame of 137 codons. FAU1P exhibits an amplification of the (AAG) triplet repeat present in the S30 coding part of FAU. FAU1P is integrated in an antisense orientation within a sequence homologous to the promoter of the islet amyloid polypeptide (IAPP or amylin)-encoding gene. By means of PCR hybrid panel mapping, FAU1P was assigned to chromosome 18.

Amyloid↗
PubMed1992

Controlling cellular development in a single cell system of Nicotiana.

Cells regenerated from freshly isolated leaf mesophyll protoplasts can be induced to develop along very different pathways. Depending on the hormone content and the mechanical characteristics of the environment, cells choose between division and expansion. In the former case they form microcolonies of isodiametric cells, while in the latter they exhibit a typical tubular growth or increase their volume considerably by bulging and budding. A culture method was developed which allows a careful control of the experimental environment and non-destructive high resolution monitoring of development of individual cells.

Cells, Cultured↗