F plasmid

Microbial genetics

1. F Plasmid Dr. P. Suganya Asssitant Professor Departemnt of Biotechnology Sri Kaliswari College ((Autonomous), Sivakasi

2. The F plasmid Is a double – stranded circular DNA molecules of about 100 kpb. F = Fertility Factor Or Sex Plasmid Its Ability to transfer chromosomal genes from a cell containing F Plasmid to one that does not. INTRODUCTION:

3. IS ELEMENT: Is an insertion sequence element or IS element. Is act as a simple transposable element. Is help to moment with the help of transposase enzyme. Tn 1000 : Is Transposed to several site. This leads to the appearance of donors transferring their chromosome from several fixed point oriT and in opposite directions. The location of these point and the direction of transfer are determined by Tn 1000 insertion site and their orientation.

4. Ori T : Origin of transfer (ori T) On transmissible plasmid DNA transfer initiate with in a cis acting Site , the origin of conjugal transfer Is a nucleotide sequence (~40 - ~500 bp length ) Ori V : The replicon is comprised of the origin of replication (ori) and all Of its control elements. The ori is the place where DNA replication begins, enabling a plasmid to Reproduce itself as it must to survive within cells

5. Tra region : The Tra locus include the pilin gene and regulatory genes, which together form pili on the cell surface of F – bacteria and initiate the conjugation. The existence of the tra region of a plasmid genome was first discovery in 197 by D avid H

6. Mechanisms: 1. F+ Bacterial Cell have surface appendage called F – pili or sex sex. Which are coded by the F Plasmid. An F= Cell has 23 pili. They are hair like structure about 2-3um length and appear as extension from the bacterial Cell wall. A single subunit protein ‘Pili’ coded by genes T ra A polymerizes into ‘Pilus’. 2. The sex pili unnecessary contact to the donor and recipient cell 3. When the tip of the F pilus contact the surface of recipient (F-) cells, mating is initiated. 4. Its has ability to self transmissible

7. 5. Number of copies / chromosome is 1 to 2 per cell 6. F+ is a Donor Cell and The F- is a recipient cell 7. F+ donor cell is transfer plasmid into F- recipient cell 8. F plasmid can replicate independently or can integrate into the chromosome, it is considered an episome. The capacity of f plasmid to integrate at different location and in either orientation on the chromosome allowed The determination. For some time F was the only known conjugative plasmid.

8. Thank You