User:JGLehman3/sandbox

Other Information and Thoughts
In Arabidopsis there are four known gene families, TAS1, TAS2, TAS3, and TAS4 which encode ta-siRNAs.

Concerning Biosynthesis and a bit about discovery, I know that Kate mentions the involvement of RDR6, but i think that it would be helpful to make the distinction that the involvement of RDR6 differentiates trans-acting siRNAs from miRNAs. The article already points out how they act in trans and are therefore different than siRNAs which require a full complement.

Discovery
Trans-acting siRNAs were discovered using Arabidopsis plants with mutant zip-1, sgs3-11, and rdr6-11 genes. mRNA of Two genes (At1g63130 and At5g18040) only accumulated in sgs3-11 and rdr-11 mutants and further study revealed that several endogenous 21-nt sRNAs were partially complementary to the mRNAs. The sRNAs were not siRNAs because they were only partially complementary, nor were they miRNAs because miRNAs do no use RDR6.