Lin-4 is a microRNA (miRNA) that was identified from a study of developmental timing in C. elegans , and was later shown to be part of a much larger class of non-coding RNAs termed miRNAs . lin-4 is found on chromosome II in C. elegans and is complementary to sequences in the 3' untranslated region (UTR) of lin-14 mRNA. lin-4 acts to developmentally repress the accumulation of lin-14 protein. lin-4 also targets lin-28 and reduces protein expression. miRNAs are transcribed as ~70 nucleotide precursors and subsequently processed by the Dicer enzyme to give a ~22 nucleotide product. The extents of the hairpin precursors are not generally known and are estimated based on hairpin prediction. The products are thought to have regulatory roles through complementarity to mRNA. The involvement of Dicer in miRNA processing suggests a relationship with the phenomenon of RNA interference.