Aim of study The objective of these studies was to analyze the implication of slicer activity of AGO1 in the following molecular processes: • loading of siRNAs and miRNAs • stability of siRNAs and miRNAs • formation of RDR6/SGS3-dependent secondary siRNAs • decay of mRNAs targeted by miRNAs The studies use point mutants defective in slicer activity and analyses total and AGO1-bound small RNA populations as well as mRNA populations in these mutants by next-generation sequencing.