Abstract: Modulation of mRNA activity is achieved with precursor miRNAs (ta-RNAs). ta-RNAs, primarily pre-miRNAs and pri-miRNAs, including truncated and mutated ta-RNAs, are employed for modulation of mRNA expression where it is found that pri- and pre-miRNA have activity independently of the presence of functional mature miRNAs. Modification of at least one of the stem and loop of the ta-RNAs to enhance binding of the ta-RNA to the target mRNA is employed. The modification may be enhanced complementarity between the ta-RNA and the target mRNA and/or improved thermodynamic efficiency in binding of the ta-RNA to the target.

Abstract: Modulation of mRNA activity is achieved with precursor miRNAs (ta-RNAs). ta-RNAs, primarily pre-miRNAs and pri-miRNAs, including truncated and mutated ta-RNAs, are employed for modulation of mRNA expression where it is found that pri- and pre-miRNA have activity independently of the presence of functional mature miRNAs. Modification of at least one of the stem and loop of the ta-RNAs to enhance binding of the ta-RNA to the target mRNA is employed. The modification may be enhanced complementarity between the ta-RNA and the target mRNA and/or improved thermodynamic efficiency in binding of the ta-RNA to the target.

Abstract: Modulation of mRNA activity is achieved with precursor miRNAs (ta-RNAs). ta-RNAs, primarily pre-miRNAs and pri-miRNAs, including truncated and mutated ta-RNAs, are employed for modulation of mRNA expression where it is found that pri- and pre-miRNA have activity independently of the presence of functional mature miRNAs. Modification of at least one of the stem and loop of the ta-RNAs to enhance binding of the ta-RNA to the target mRNA is employed. The modification may be enhanced complementarity between the ta-RNA and the target mRNA and/or improved thermodynamic efficiency in binding of the ta-RNA to the target.

Abstract: By modifying nucleotides from either or both the stem and loop of precursor-miRNA, greater specificity is achieved as to the mRNAs targeted. The improved efficiency in target regulation can be either mediated by direct base-pairings between targets and precursor miRNAs or indirectly by energy constraints on the availability of such base-pairings. It is found that pri- and pre-miRNA are active in the absence of functional mature miRNA, so pri- or pre-miRNA or truncated portion thereof, but not as mature miRNA, can be used as RNAi agents by themselves. Furthermore, besides the seed sequence of the stem of the pre-miRNA and 3?-extensions thereof to provide greater complementarity to the target mRNA, nucleotides in the loop can affect the activity and specificity of the precursor-miRNA and the processing and binding to target mRNA.