A temporal gradient of the novel nuclear protein LIN-14 specifies the timing and sequence of stage-specific developmental events in Caenorhabditis elegans. The profound effects of
lin-14 mutations on worm development suggest that LIN-14 directly or indirectly regulates stage-specific gene expression. We show that LIN-14 can associate with chromatin in vivo and has in vitro DNA binding activity. A bacterially expressed C-terminal domain of LIN-14 was used to select DNA sequences that contain a putative consensus binding site from a pool of randomized double-stranded oligonucleotides. To identify candidates for genes directly regulated by
lin-14, we employed DNA microarray hybridization to compare the mRNA abundance of C. elegans genes in wild-type animals to that in mutants with reduced or elevated
lin-14 activity. Five of the candidate LIN-14 target genes identified by microarrays, including the insulin/insulin-like growth factor family gene
ins-33, contain putative LIN-14 consensus sites in their upstream DNA sequences. Genetic analysis indicates that the developmental regulation of
ins-33 mRNA involves the stage-specific repression of
ins-33 transcription by LIN-14 via sequence-specific DNA binding. These results reinforce the conclusion that
lin-14 encodes a novel class of transcription factor. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Keywords: Logical Set