Project description:Analyses of new genomic, transcriptomic or proteomic data commonly result in trashing many unidentified data escaping the ‘canonical’ DNA-RNA-protein scheme. Testing systematic exchanges of nucleotides over long stretches produces inversed RNA pieces (here named “swinger” RNA) differing from their template DNA. These may explain some trashed data. Here analyses of genomic, transcriptomic and proteomic data of the pathogenic Tropheryma whipplei according to canonical genomic, transcriptomic and translational 'rules' resulted in trashing 58.9% of DNA, 37.7% RNA and about 85% of mass spectra (corresponding to peptides). In the trash, we found numerous DNA/RNA fragments compatible with “swinger” polymerization. Genomic sequences covered by «swinger» DNA and RNA are 3X more frequent than expected by chance and explained 12.4 and 20.8% of the rejected DNA and RNA sequences, respectively. As for peptides, several match with “swinger” RNAs, including some chimera, translated from both regular, and «swinger» transcripts, notably for ribosomal RNAs. Congruence of DNA, RNA and peptides resulting from the same swinging process suggest that systematic nucleotide exchanges increase coding potential, and may add to evolutionary diversification of bacterial populations.
Project description:Severe loss-of-function alleles of DCL1 are embryonic lethal. Defects in cell division were seen as early as the globular stage in the strong loss-of-function allele dcl1-15. Phenotypic work with dcl1-15 and the null allele dcl1-5 suggested that, in addition to the severe patterning defects, the mutants were maturing earlier than wild-type embryos. We performed global gene expression analysis of dcl1-15 and wild-type torpedo staged embryos to examine this maturation phenotype further. The results suggested that DCL1 is a heterochronic gene. Comparisons to a time series of embryo development (http://www.seedgenenetwork.net/arabidopsis) showed that the genes differentially expressed in dcl1-15 embryos behaved more like green-cotyledon stage embryos than torpedo embryos. Seeds of a DCL1/dcl1-15 plant were sown. For each wild-type sample, 300 torpedo stage embryos were selected from wild-type siblings. For each mutant replicate, 300 dcl1-15/dcl1-15 embryos were selected from the siliques of DCL1/dcl1-15 where the wild-type embryos were at the torpedo stage.