Protein truncation test (PTT)

The key features of PTT are (i) that the analysis is based on the
protein product generated from the DNA sequence, and
(ii) the method specifically detects premature protein
truncation caused by non-sense mutations. The PCR product is
transcribed and translated in vitro by a reticulocyte lysate,
during which the nascent protein product is radiolabelled with
35S-labelled amino acids. The translation products are then
separated by polyacrylamide gel electrophoresis. Samples with
non-sense mutations are detected by their tendency to
generate smaller protein products than their normal
counterparts.