RNA molecules or RNA-Protein complexes endowed with catalytic (enzymatic) activity and capable of cleaving mRNA molecules in a sequence specific catalytic manner.
Ribozyme Technology:
Use of ribozymes for different purposes including therapeutic and research purposes.
Types of Ribozymes:
- Natural Ribozymes, such as, Hairpin, Hammerhead, Hepatitis Delta Virus (HDV), Varkud Satellite (VS), glms etc.
- Group – I and group – II introns, such as, spliceosomes, RNase P.
Properties of Ribozymes:
- Active-site entirely composed of RNA.
- RNA provides catalytic / enzymatic activity.
- Capable of cleaving m-RNA molecules in a sequence-specific catalytic manner.
- Contains sequences for selective ligation with target m-RNA, therefore, highly specific.
- Tailorable i.e. substrate-recoginising sequences can be tailored specifically to suppress genes / silencing of genes.
- Can prevent translation of a particular m-RNA.
- Can be packaged into viral vectors.
Occurrence:
- Group-I intron ribozymes: Bacteria, lower eukaryotes, higher plants.
- Group-II intron ribozymes: Bacteria, Mitochondrial and Chloroplast genomes of fungi, plants, protists and annelid worm.
- RNase-P: all living organisms (as an essential t-RNA processing enzyme).
Specific functions of some ribozymes:
- Hammerhead ribozyme: cleaves single-stranded (ss) RNA.
- Spliceosome: removes introns from a transcribed pre-mRNA.
- Hairpin ribozyme: catalyzes RNA-processing reactions essential for replication of satellite mRNA molecules. Can perform cleaving as well as ligation reactions with the help of ribozyme motif.
Applications of ribozyme technology:
- Cleaving RNA-molecules.
- Inhibit gene expression / to do gene silencing.
- Gene therapy.
- Treatment of diseases like HIV via synthetic ribozymes.
- Tool for molecular and cell biologists (generate loss of function phenotypes, attenuate gene expression, gene function analysis, controllable therapeutic agents).
- RNA interference therapeutics.
- RNase P is involved in processing of precursor t-RNA.