Long intergenic non-coding RNAs (lincRNAs) act as regulatory elements or motifs of a variety of biological processes in living organisms. In an attempt to find all lincRNAs and to assign them with functions in C. elegans, we identified
linc-171, lacking a (or containing a very short) poly (A) tail, might positively regulate its nearby protein coding gene,
c25a1.5, in trans. By a series of genetic analyses, we found that
linc-171 possessed specific expression pattern and worked downstream of PHA-4. Knocking down
linc-171 by RNAi or large truncation of
linc-171 locus led to significantly increased dauer formation and this enhancement was
daf-12 dependent. Furthermore, phenotypes caused by
linc-171 RNAi or truncated
linc-171 could be rescued by
c25a1.5 or its human homolog, FA2H, both of which encode a fatty acid hydroxylase that is required for 2'-hydroxy ceramide synthesis. Since ceramide has already been implicated in cell growth arrest control, our experiments suggest that
linc-171 may control worm dauer development or developmental arrest through regulating
c25a1.5 and reveal important biological function(s) of a non-mRNA like lincRNA in C. elegans.