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Gene Shows (gene + shows)
Selected AbstractsCloning a novel developmental regulating gene, Xotx5: Its potential role in anterior formation in Xenopus laevisDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 2 2000Hiroki Kuroda The vertebrate Otx gene family is related to otd, a gene contributing to head development in Drosophila. In Xenopus, Xotx1, Xotx2, and Xotx4 have already been isolated and analyzed. Here the cloning, developmental expression and functions of the additional Otx Xenopus gene, Xotx5 are reported. This latter gene shows a greater degree of homology to Xotx2 than Xotx1 and Xotx4. Xotx5 was initially expressed in Spemann's organizer and later in the anterior region. Ectopic expression of Xotx5 had similar effects to other Xotx genes in impairing trunk and tail development, and especially similar effects to Xotx2 in causing secondary cement glands. Taken together, these findings suggest that Xotx5 stimulates the formation of the anterior regions and represses the formation of posterior structures similar to Xotx2. [source] Evaluation of potential regulatory elements identified as DNase I hypersensitive sites in the CFTR geneFEBS JOURNAL, Issue 2 2002Marios Phylactides The cystic fibrosis transmembrane conductance regulator (CFTR) gene shows a complex pattern of expression, with temporal and spatial regulation that is not accounted for by elements in the promoter. One approach to identifying the regulatory elements for CFTR is the mapping of DNase I hypersensitive sites (DHS) within the locus. We previously identified at least 12 clusters of DHS across the CFTR gene and here further evaluate DHS in introns 2, 3, 10, 16, 17a, 18, 20 and 21 to assess their functional importance in regulation of CFTR gene expression. Transient transfections of enhan- cer/reporter constructs containing the DHS regions showed that those in introns 20 and 21 augmented the activity of the CFTR promoter. Structural analysis of the DNA sequence at the DHS suggested that only the one intron 21 might be caused by inherent DNA structures. Cell specificity of the DHS suggested a role for the DHS in introns 2 and 18 in CFTR expression in some pancreatic duct cells. Finally, regulatory elements at the DHS in introns 10 and 18 may contribute to upregulation of CFTR gene transcription by forskolin and mitomycin C, respectively. These data support a model of regulation of expression of the CFTR gene in which multiple elements contribute to tightly co-ordinated expression in vivo. [source] Cloning and characterization of a trypsin-encoding cDNA of the human body louse Pediculus humanusINSECT MOLECULAR BIOLOGY, Issue 1 2004A. H. Kollien Abstract From a cDNA library of the whole insect, a trypsin gene of Pediculus humanus has been cloned and sequenced. The 908 bp clone has an open reading frame of 759 bp, which encodes a pre-proenzyme with 253 amino acid residues. A sixteen-residue N-terminal signal peptide is followed by a twelve-residue activation peptide with putative cleavage sites at Gly16 and Tyr28. The deduced amino acid sequence has several features typical of trypsin proteases and an overall identity of 35,43% with the trypsins of several haematophagous Diptera. The 1.0 kb genomic trypsin gene contains three introns of 102, 79 and 80 nucleotides following the codons for Gly16, Gln74 and Ala155, respectively. Only a single gene seems to be present. In Northern blot analysis, unfed first instar larvae have an identical or slightly lower level of trypsin mRNA than fed adult lice, and in adults 2,24 h after the bloodmeal this gene shows a constitutive expression. After in vitro transcription and translation, the activation peptide is cleaved by chymotrypsin, a so far unreported phenomenon in trypsin activation. [source] Cardiac troponin T Arg92Trp mutation and progression from hypertrophic to dilated cardiomyopathyCLINICAL CARDIOLOGY, Issue 5 2001Noboru Fujino M.D. Abstract Background: Mutations in the cardiac troponin T gene causing familial hypertrophic cardiomyopathy (HCM) are associated with a very poor prognosis but only mild hypertrophy. To date, the serial morphologic changes in patients with HCM linked to cardiac troponin T gene mutations have not been reported. Hypothesis: The aim of this study was to determine the long-term course of patients with familial HCM caused by the cardiac troponin T gene mutation, Arg92Trp. Results: The Arg92Trp missense mutation was present in 10 individuals from two unrelated pedigrees. They exhibited different cardiac morphologies: three had dilated cardiomyopathy-like features, five had asymmetric septal hypertrophy with normal left ventricular systolic function, one had electrocardiographic abnormalities without hypertrophy, and one had the disease-causing mutation but did not fulfill the clinical criteria for the disease. The mean maximum wall thickness was 14.1 ± 6.0 mm. The three patients with dilated cardiomyopathy-like features had progressive left ventricular dilation. Three individuals underwent right ventricular endomyocardial biopsy. There was a modest degree of myocardial hypertrophy (myocyte diameter: 18.9 ± 5.2 m,m), and minimal myocardial disarray and mild fibrosis were noted. Conclusion: The Arg92Trp substitution in the cardiac troponin T gene shows a high degree of penetrance, moderate hypertrophy, and early progression to dilated cardiomyopathy in Japanese patients. Early identification of individuals with this mutation may provide the opportunity to evaluate the efficacy of early therapeutic interventions. [source] Expression of Hoxa-11 and Hoxa-13 in the pectoral fin of a basal ray-finned fish, Polyodon spathula: implications for the origin of tetrapod limbsEVOLUTION AND DEVELOPMENT, Issue 3 2005Brian D. Metscher Summary Paleontological and anatomical evidence suggests that the autopodium (hand or foot) is a novel feature that distinguishes limbs from fins, while the upper and lower limb (stylopod and zeugopod) are homologous to parts of the sarcopterygian paired fins. In tetrapod limb development Hoxa-11 plays a key role in differentiating the lower limb and Hoxa-13 plays a key role in differentiating the autopodium. It is thus important to determine the ancestral functions of these genes in order to understand the developmental genetic changes that led to the origin of the tetrapod autopodium. In particular it is important to understand which features of gene expression are derived in tetrapods and which are ancestral in bony fishes. To address these questions we cloned and sequenced the Hoxa-11 and Hoxa-13 genes from the North American paddlefish, Polyodon spathula, a basal ray-finned fish that has a pectoral fin morphology resembling that of primitive bony fishes ancestral to the tetrapod lineage. Sequence analysis of these genes shows that they are not orthologous to the duplicated zebrafish and fugu genes. This implies that the paddlefish has not duplicated its HoxA cluster, unlike zebrafish and fugu. The expression of Hoxa-11 and Hoxa-13 in the pectoral fins shows two main phases: an early phase in which Hoxa-11 is expressed proximally and Hoxa-13 is expressed distally, and a later phase in which Hoxa-11 and Hoxa-13 broadly overlap in the distal mesenchyme of the fin bud but are absent in the proximal fin bud. Hence the distal polarity of Hoxa-13 expression seen in tetrapods is likely to be an ancestral feature of paired appendage development. The main difference in HoxA gene expression between fin and limb development is that in tetrapods (with the exception of newts) Hoxa-11 expression is suppressed by Hoxa-13 in the distal limb bud mesenchyme. There is, however, a short period of limb bud development where Hoxa-11 and Hoxa-13 overlap similarly to the late expression seen in zebrafish and paddlefish. We conclude that the early expression pattern in tetrapods is similar to that seen in late fin development and that the local exclusion by Hoxa-13 of Hoxa-11 from the distal limb bud is a derived feature of limb developmental regulation. [source] Analysis of the VCX3A, VCX2 and VCX3B genes shows that VCX3A gene deletion is not sufficient to result in mental retardation in X-linked ichthyosisBRITISH JOURNAL OF DERMATOLOGY, Issue 3 2008S.A. Cuevas-Covarrubias Summary Background, X-linked ichthyosis (XLI), an inborn error of metabolism, is due to steroid sulphatase (STS) deficiency. Most patients with XLI harbour complete deletion of the STS gene and flanking sequences. The presence of low copy number repeats on either side of the STS gene seems to have a major role in the high frequency of these deletions. Some patients with XLI with terminal deletions of Xp22.3 involving marker DXS1139 and the STS gene show mental retardation (MR); VCX3A is the only gene located on this critical region. Objectives, To analyse the VCX3A, VCX, VCX2 and VCX3B genes in 80 unrelated Mexican patients with XLI with normal intelligence. Methods, STS activity was measured in the leucocytes using 7-[3H]-dehydroepiandrosterone sulphate as a substrate. Amplification of the regions from telomeric DXS89 to centromeric DXS1134 including both extremes of the STS and the VCX3A, VCX, VCX2 and VCX3B genes was performed using polymerase chain reaction. Results, No STS activity was detected in the patients with XLI (0·00 pmol mg,1 protein h,1). We observed two different deletion patterns: the first group included 62 patients with deletion of VCX3A and VCX genes. The second group included 18 patients with breakpoints at several regions on either side of the STS gene not including the VCX3A gene. Conclusions, These data indicate that more complex mechanisms, apart from possible VCX3A gene participation, are occurring in the genesis of MR in XLI, at least in the sample of Mexican patients analysed. [source] | |||||||||||||