Altered patterns of gene expression in Tribolium segmentation mutants.

Embryos homozygous for the godzilla, jaws, or kraken mutations of Tribolium castaneum have characteristic defects in segmentation. Here, we examine the expression of Tribolium genes homologous to Drosophila segmentation genes in these mutants to define similarities and differences in the process of segmentation in the two insects. The godzilla mutation disrupts segmentation and alters the expression of Even-skipped (Eve) throughout the germ band.

Embryonic patterning mutants of Tribolium castaneum.

The identification and analysis of genes controlling segmentation in Drosophila melanogaster has opened the way for understanding similarities and differences in mechanisms of segmentation among the insects. Homologues of Drosophila segmentation genes have been cloned and their expression patterns have been analyzed in a variety of insects, revealing that the patterns of expression of many genes are conserved. Conserved expression patterns do not, however, necessarily reflect conserved gene function.

Mutations affecting the meiotic and mitotic divisions of the early Caenorhabditis elegans embryo.

We describe interactions between maternal-effect lethal mutations in four genes of Caenorhabditis elegans whose products appear to be involved in the meiotic and mitotic divisions of the one-cell embryo. Mitosis is disrupted by two dominant temperature-sensitive gain-of-function maternal-effect lethal mutations, mei-1(ct46) and mel-26(ct61), and by recessive loss-of-function maternal-effect lethal mutations of zyg-9. The phenotypic defects resulting from these mutations are similar.

2'-O-alkyl oligoribonucleotides as antisense probes.

2'-O-Methyl oligoribonucleotides have recently been introduced as antisense probes for studying RNA processing and for affinity purification of RNA-protein complexes. To identify RNA analogues with improved properties for antisense analysis, 2'-O-alkyl oligoribonucleotides were synthesized in which the alkyl moiety was either the three-carbon linear allyl group or the five-carbon branched 3,3-dimethylallyl group. Both these analogues were found to be completely resistant to degradation by either DNA- or RNA-specific nucleases.

Synthesis and applications of oligoribonucleotides with selected 2'-O-methylation using the 2'-O-[1-(2-fluorophenyl)-4-methoxypiperidin-4-yl] protecting group.

The synthesis of base protected 5'-O-dimethoxytrityl-2'-O-[1-(2- fluorophenyl)-4-methoxypiperidin-4-yl]-3'-O-(2-cyanoethyl N,N-diisopropylphosphoramidites) is described, using phenoxyacetyl protection for the exocyclic amino groups of guanosine and adenosine and acetyl protection of the amino group of cytidine. High yield assembly of these building blocks into oligoribonucleotides on aminopropyl controlled pore glass was achieved using 5-(4-nitrophenyl)-1H-tetrazole as activator. Mixed sequences containing selected 2'-O-methylation were also synthesised and their significance for the study of RNA biochemistry is discussed.