Users' questions

What is the function of tra gene products of F plasmid?

What is the function of tra gene products of F plasmid?

Transfer genes or tra genes (also transfer operons or tra operons), are some genes necessary for non-sexual transfer of genetic material in both gram-positive and gram-negative bacteria.

What is an F plasmid in conjugation?

coli or the F sex factor; also called F-plasmid) allows genes to be transferred from one bacterium carrying the factor to another bacterium lacking the factor by conjugation. The F plasmid belongs to a class of conjugative plasmids that control sexual functions of bacteria with a fertility inhibition (Fin) system.

What is the size range of plasmid DNA?

The size of the plasmid varies from 1 to over 200 kbp, and the number of identical plasmids in a single cell can range anywhere from one to thousands under some circumstances.

What is encoded by the transfer region of the F plasmid?

The F factor encodes genes for sexual pili, thin rod-like structures with which F-carrying (male or donor) bacteria attach to F− (female or recipient) cells for conjugative transfer. The F factor carries an operon of about 30 genes, encoding Tra proteins promoting transfer (Figure 1).

Why are tra genes important for the propagation of plasmid?

The tra genes encode proteins which are useful for the propagation of the plasmid from the host cell to a compatible donor cell or maintenance of the plasmid. Not all transfer operons are the same. Some genes are only found in a few species or a single genus of bacteria while others…

When was the tra region of the genome discovered?

The existence of the tra region of a plasmid genome was first discovered in 1979 by David H. Figurski and Donald R. Helinski In the course of their work, Figurski and Helinski also discovered a second key fact about the tra region – that it can act in trans to the mobilization marker which it affects.

What are the functions of the tra genes?

The tra genes encode proteins which are useful for the propagation of the plasmid from the host cell to a compatible donor cell or maintenance of the plasmid. Not all transfer operons are the same.

Where does integration of F plasmid take place?

Integration of F Plasmid into the Bacterial Chromosome: Integration of the F factor into the bacterial chromosome occurs at specific regions of DNA called insertion sequences (IS) (Fig. 18.2, 18.3). The F factor carries several IS regions, such as, IS 2, IS 3, V-δ.