Comment on:

Science. 1999 Oct 29;286(5441):886.

A species of small antisense RNA in posttranscriptional gene silencing in plants.

Sainsbury Laboratory, John Innes Centre, Colney Lane, Norwich NR4 7UH, UK.

Posttranscriptional gene silencing (PTGS) is a nucleotide sequence-specific defense mechanism that can target both cellular and viral mRNAs. Here, three types of transgene-induced PTGS and one example of virus-induced PTGS were analyzed in plants. In each case, antisense RNA complementary to the targeted mRNA was detected. These RNA molecules were of a uniform length, estimated at 25 nucleotides, and their accumulation required either transgene sense transcription or RNA virus replication. Thus, the 25-nucleotide antisense RNA is likely synthesized from an RNA template and may represent the specificity determinant of PTGS.

PMID: 10542148 [PubMed - indexed for MEDLINE]