Microinjection

a proper description about the process microinjection and also about gene transfer. and different types of DNA delivery methods.
with advantages, disadvantages, limitations and applications.

1. MICROINJECTION NIKITA NARWAL B.Sc. Biotechnology (final year) Roll no:194713 Ph. No.:9896989063

2. WHAT IS GENE TRANSFER? It is defined simply as a technique to efficiency and stably introduce foreign genes into the genome of target cells. The insertion of unrelated, therapeutic genetic information in the form of DNA into target cells .

3. GENE TRANSFER TECHNIQUE Based on the vectors used the gene transfer techniques can be divided as, 1. Non-Viral methods. 2. Viral method.

4. NON-VIRAL DELIVERY SYSTEM Non-viral vectors using mechanical or chemical approaches can efficiently transfect cells in vitro. Mechanical methods involve direct injection or the use of “gene gun technology” to introduce the plasmid DNA. LIMITATIONS Low levels of gene expression. Inability to use for systemic administration due to the presence of serum nucleases.

5. GENERALLY THERE ARE TWO APPROACHES OF DNA TRANSFER Natural method of DNA transfer Artificial method of DNA transfer

6. NATURAL METHOS OF DNA TRANSFER

7. ARTIFICIAL METHOD OF DNA TRANSFER

8. MICROINJECTION Microinjection where the DNA is directly injected into plant protoplast or cells (specifically into the nucleus or cytoplasm) using fine tipped(0.5-1.0 micrometer diameter) glass needle or micropipette. This method of gene transfer is used to introduce DNA into large cells, normally performed under a specialized optical microscope setup called a micromanipulator. The process is frequently used as a vector in genetic engineering and transgenetics to insert material into a single cell. Computerized control of holding pipette, needle, microscope stage and video technology has improved the efficiency of this technique .

9. ADVANTAGES OF MICROINJECTION Frequency of stable integration of DNA is far better as compared to other method. Method is effective in transforming primary cells as well as cells in established culture. The DNA injected in this process is subjected to less extensive modification. More precise integration of recombinant gene in limited copy number can be obtained .

10. LIMITATIONS OF MICROINJECTION Costly. Skilled personal required. More useful for animal cells. Embryonic cells are preferred for manipulation. Knowledge of mating timing, oocyte recovery is essential. Methos is useful for protopplast and not for the walled cells.

11. APPLICATIONS OF MICROINJECTION Process is applicable for plant cells as well as animal cells but more common for animal cells. Technique is ideally useful for producing transgenic animal quickly. Procedure is important for gene transfer to embryonic cells. Applied to inject DNA into plant nuclei. Method has been successfully used with cells and protoplast of tobacco, alfalfa etc.

12. Microinjection is potentially a useful method for simultaneous introduction of multiple bioactive compounds such as antibodies, peptides, RNAs, plasmid, diffusion markers, elicitors, Ca2+ as well as nucleus and artificial micro or nano particles containing those chemicals into the same target-cells.