The protein truncation test (ptt) gives an uncommon exception, targeting mutations that create shortened proteins, majorly premature translation termination. Ptt has various attractive features, involving pinpointing the site of a mutation, a low false-positive rate, good sensitivity, and, more esssentially, the near-exclusive highlighting of disease-causing mutations. Additionally, ptt initiated the detection of a new mutation type, that is, a sequence change creating a hypermutable region surfacing in rna. This technique takes rna as template and scans for mutations at protein level.
Protein truncation test includes four steps
1. Isolation of nucleic acid, that is, total rna, genomic dna or poly (a) rna.
2. Amplification of particular gene of interest
3. In vitro translation and transcription of the product of amplification reaction
4. Identification of translation of the products through autoradiography.
The shorter protein products of the mutant alleles are simply distinguished from the full length protein of mutant allele.