METHODS OF GENE TRANSFER : METHODS OF GENE TRANSFER PRESENTED BY- POONAM VERMA B.TECH(BIOTECHNOLOGY) 3 rd YEAR There are three methods of Gene Tranfer :: There are three methods of Gene Tranfer : MICROINJECTION ELECTROPORATION MICROPROJECTILE PowerPoint Presentation: MICROINJECTION:- The microinjection is the process of transferring the desirable DNA into the living cell ,through the use of glass micropipette . This glass micropipette is usually of 0.5 to 5 micrometer,that easily penetrates into the cell membrane and nuclear envelope. The desired gene is then injected into the sub cellular compartment and needle is removed. Microinjection: Microinjection PowerPoint Presentation: APPLICATION OF MICROINJECTION:- - THIS Process is frequently used as a vector in genetic engineering and transgenics. -THIS method of gene transfer is used to introduced DNA into large cell such as zygote. PowerPoint Presentation: ELECTROPORATION :- Electroporation involves a pulse of high voltage applied to protoplast ,cell,tissue to make transient pores in the plasma membrane which facilitates the uptake of foreign DNA. The CELLS are placed in a solution containing DNA and subjected to electrical pulse to cause holes in the membrane. The foreign DNA fragments enter through holes into the cytoplasm and then to nucleus. It depends on local transmembrane voltage at each point on the membrane. A threshold voltage is maintain,generally applied voltage is :- 0.5v to 1 v. ADVANTAGE :: ADVANTAGE : Versatilty :-Electroporation is effective with nearly all cell and species types. Efficiency:-A large majority of cells take in the target DNA . Small size:-The amount of DNA required is small than other method. PowerPoint Presentation: DISADVANTAGES:- CELL DAMAGE:- if the pulses are of higher intensity ,some pores may become too large or fail to close, after membrane discharge causing cell damage. NON SPECIFIC:-THE transport of material into and out of the cell during the time of electropermeability is non specific.THIS may result in an ion imbalance,or improper cell function. APPLICATION :- : APPLICATION :- In molecular biology ,the process of electroporation is often used for transformation of bacteria,yeast,and plant protoplast. In Gene Therapy MICROPROJECTILE :-: MICROPROJECTILE :- MICROPROJECTILE BOMBARDMENT is a method by which foreign substances such as DNA are introduced into living cell and tissue through high velocity microprojectiles. Also called as gene gun method and biolistic particle gun method. 1-3 micrometer tungsten or gold particle coated DNA (macrocarrier). After entered into the cell ,DNA are detached from tungsten and enter inside the nucleus. PowerPoint Presentation: APPLICATION: Bombardement of plant tissue with projectiles it is an effective method of wounding to promote agrobacterium mediated tranformation. Transformation of sugarcane meristem .