Process for producing stabilised RNA molecules within cells, RNA molecules thus produced and nucleic acid precursors of such molecules

The invention concerns a process for producing stabilised non-translated RNA molecules within a cell, comprising introducing into a plant or yeast cell a nucleic acid molecule comprising a &lang&&lang& precursor DNA &rang&&rang&, said precursor DNA containing a coding sequence, or a cluster of coding sequences, each coding sequence encoding : a non-translated RNA sequence to be stabilised, which is capable of functionally interacting with a cellular component, and stabilising sequences comprising at least one protein binding site and, optionally, sequences capable of giving rise to secondary structure associated with said protein binding site, said stabilising sequences being heterologous with respect to the non-translated RNA sequence to be stabilised, the precursor DNA being under the transcriptional control of regulatory sequences functional in said cell, whereby a transcript is produced by transcription of the precursor DNA, and one or more stabilised RNA units comprising the non-translated RNA sequence in association with the stabilising sequences is, or are, then produced by processing of the transcript by the cell's endogenous processing machinery.