For insertion of DNA into a suitable vector several methods are used and homopolymer tailing is one of them. Which specific enzyme is used in this method to synthesize homopolymer tail ?
MH SET - 2023, SET Exam - 2023,
Answer: C
Homopolymer tails are made by Terminal deoxynucleotidyl transferase.
Terminal transferase adds nucleotides to the 3'-OH ends of DNA without a template. Given only one deoxynucleotide, for example dCTP, it builds a tail of that base alone. In homopolymer tailing the vector is tailed with one base (say poly-dG) and the insert with the complementary base (poly-dC), so the two anneal through their tails.
T4 DNA ligase joins DNA ends by forming phosphodiester bonds but does not add nucleotides. Polynucleotide kinase adds a phosphate to 5'-OH ends. S1 nuclease removes single-stranded DNA, which would trim tails rather than build them.
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