Arrest of Translation to Assay for DNA of a Gene
In vitro translation of mRNA forms the basis of one technique foridentification of clones containing DNA of a particular gene. The technique requires that the enriched messenger RNA of the gene, such as the mRNA obtained from an oligo-dT column, be translatable in vitro to yield a detectable protein product of the desired gene. To perform the identification, DNA for a candidate clone is denatured and hybridized to the RNA used in the translation mixture. If the DNA contains sequences complementary to the mRNA, the two will hybridize to-gether, the messenger will become unavailable for in vitro translation, and the gene product will not be synthesized (Fig. 9.15). DNA from a clone not possessing the DNA sequence of the gene will not interfere
Figure 9.15 Hybridization arrest of translation as an assay for DNA of a genewhose mRNA can be translated into protein.
with translation of the messenger. Hence DNA carrying sequences complementary to the messenger can be detected by hybridization arrest of translation.