HOMOPOLYMER TAILING.pptx
- 1. SEMESTER – IV BIOTECHNOLOGY SEMINAR TOPIC : HOMOPOLYMER TAILING SUBMITTED BY, S. JENIFER JULIE II M.SC MICROBIOLOGY REG NO : 20201232516107 SUBBMITED TO, Dr. G. RAMANADHAN DEPARTMENT OF MICROBIOLOGY
- 2. INTRODUCTION • A homopolymer is a polymer where all the subunits are same. • Tailing is the adding a series of nucleotides on to the 3’ –OH termini of a double stranded DNA molecule using enzyme terminal deoxynucleotidyl transferase of calf thymus. • In homopolymer tailing , gene of interest is tailed with one nucleotide and vector is tailed with an complemetary base.
- 3. • It is the method for joining DNA molecules by annealing of complementary homopolymer sequence. • Oligo(dA) sequences is added to the 3’ ends of the molecule and oligo(dA) blocks to the 3’end of another molecule. • This method is catalyzed by enzyme terminal deoxynucleotidyl transferase by addition of nucleotides to the 3’ end of a DNA fragment.
- 6. PROCESS • They are then allowed to incubate together to allow hydrogen bonding to bring them together . • Homopolymer tailing is achieved by annealing. • It is a technique by which sticky ends can be produced on an blunt-ended DNA molcule. • The reaction when carrid out in the presence of on deoxynucleotide a homopolmer tail is produced.
- 8. • For ligation of two tailed molecules the homopolymers must be complementary. • Poly dC tails are attached to the vector and poly dG to the DNA to be cloned.
- 9. USES OF HOMOPOLYMER TAILING • This is more widely used approach for making recombinant DNA. • Segments of 50-100 poly A and poly G are added to one fragment. • Equal length segments of poly-T and poly-C are added to the other fragment.
- 10. Homopolymer tailing to provide a priming site for second strand synthesis. Dark blue shaded material is DNA. The light blue shaded material is RNA.
- 11. Thank You.....