The present invention relates to the production of novel, recombinant polynucleotides comprising the GIR1 ribozyme, or a variant thereof, vectors comprising such polynucleotides and recombinant host cells comprising such polynucleotides and/or such vectors. The invention furthermore relates to the use of said polynucleotides in the treatment of an individual suffering from a disease associated with or caused by instability of a transcript of said second subsequence such as cancer, cachexia, .alpha.-Thallasemia or leukaemia.