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.
