Search

We address a controversy over use of the term “gene drive” to include both natural and synthetic genetic elements that promote their own transmission within a population, arguing that this broad definition is both practical and has advantages for risk analysis.

Genes linked to brahma (brm), a stimulator of homeotic gene expression in Drosophila, were screened to establish possible regulators of Hox gene expression. brg1, a cloned murine gene, may be a DNA-dependent ATPase or a helicase, because it encodes a member of the DEGH proteins family. Hox gene regulation and other regulatory routes may involve the action of brg1.

The Antennapedia Complex (ANT-C) of Drosophila (D) pseudoobscura was cloned to determine the rigidity of its organization and to provide further understanding of its evolutionary changes. Results revealed that the structural characteristics of ANT-C in D pseudoobscura is highly identical with that found in D melanogaster, except that the psudoobscura ANT-C lacks the z2 gene. In addition, in D pseudoobscura, the Deformed gene's orientation is inverted and has a 5' to 3' transcription direction. These indicate that the ANT-C structure is not rigid and can be altered even during a short period of evolutionary divergence.

Determines the activation of Wnt/beta-catenin pathway in human colon cancers. Effect of beta-catenin antisense oligodeoxynucleotides on the level of axin2 and human naked cuticle (hnkd) mRNA; Expression of axin2 and hnkd in colon cancer cell lines; Correlation of the increased expression of axin2 and hnkd with truncations in polyposis coli.

The Additional sex combs (Asx) gene of Drosophila is an Enhancer of trithorax and Polycomb (ETP), and is required to maintain activation and silencing of homeotic loci. The molecular basis of this dual function is not understood. Here, we identify a human homolog of Asx, termed ADDITIONAL SEX COMBS-LIKE 1 (ASXL1). Overall, the amino acid sequence of ASXL1 has 21% identity and 41% similarity to Drosophila ASX. The ASXL1 protein contains a 118 amino acid conserved amino terminal region of unknown function that we term the ASX homology domain (ASXH) that contains two LXXLL consensus sequences for nuclear receptor binding. ASXL1 also contains a conserved C-terminal cysteine cluster that is a variant of the PHD domain. Three ASXL1 transcripts of differing size are detected, which are widely expressed in adult tissues. ASXL1 maps to chromosome 20q11, a region frequently amplified in human tumors. Interestingly, ASXL1 is overexpressed in cell lines derived from carcinomas. [Copyright &y& Elsevier]

To evaluate whether beta-catenin signaling has a role in the regulation of angiogenesis in colon cancer, a series of angiogenesis-related gene promoters was analyzed for beta-catenin/TCF binding sites. Strikingly, the gene promoter of human vascular endothelial growth factor (VEGF, or VEGF-A) contains seven consensus binding sites for beta-catenin/TCF. Analysis of laser capture microdissected human colon cancer tissue indicated a direct correlation between up-regulation of VEGF-A expression and adenomatous polyposis coli (APC) mutational status (activation of beta-catenin signaling) in primary tumors. In metastases, this correlation was not observed. Analysis by immunohistochemistry of intestinal polyps in mice heterozygous for the multiple intestinal neoplasia gene (Min/+) at 5 months revealed an increase and redistribution of VEGF-A in proximity to those cells expressing nuclear beta-catenin with a corresponding increase in vessel density. Transfection of normal colon epithelial cells with activated beta-catenin up-regulated levels of VEGF-A mRNA and protein by 250-300%. When colon cancer cells with elevated beta-catenin levels were treated with beta-catenin antisense oligodeoxynucleotides, VEGF-A expression was reduced by more than 50%. Taken together, our observations indicate a close link between beta-catenin signaling and the regulation of VEGF-A expression in colon cancer.