Identification of trans-acting siRNAs in moss and an RNA-dependent RNA polymerase required for their biogenesis.

Trans-acting small interfering RNAs (tasiRNAs) are a class of higher-plant endogenous siRNAs that, like miRNAs, direct the cleavage of non-identical transcripts. tasiRNAs derive from non-coding transcripts (TAS) that are converted into dsRNA by a RNA-dependent RNA polymerase (RDR6), following their initial miRNA-guided cleavage. The dsRNA is then processed by a dicer-like enzyme 4 into phased 21-nucleotide siRNAs.

Novel micro-RNAs and intermediates of micro-RNA biogenesis from moss.

Micro-RNAs (miRNAs) are one class of small non-coding RNAs that have important regulatory roles in higher plants. Much less is known about their prevalence and function in lower land plants. Previously we cloned 100 non-structural small RNAs from the moss Physcomitrella patens but could annotate only 11 as miRNAs.

Cloning and characterization of micro-RNAs from moss.

Micro-RNAs (miRNAs) are one class of endogenous tiny RNAs that play important regulatory roles in plant development and responses to external stimuli. To date, miRNAs have been cloned from higher plants such as Arabidopsis, rice and pumpkin, and there is limited information on their identity in lower plants including Bryophytes. Bryophytes are among the oldest groups of land plants among the earth's flora, and are important for our understanding of the transition to life on land.