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The F-plasmid (first named F by one of its discoverers Esther Lederberg；also called the sex factor in E. coli，the F sex factor, or the fertility factor) [1] [2] [3] allows genes to be transferred from one bacterium carrying the factor to another bacterium lacking the factor by conjugation. The F factor was the first plasmid to be
The fertility plasmid or F-plasmid was discovered by Esther Lederberg and encodes information for the biosynthesis of sex pilus to aid in bacterial conjugation. Conjugation involves using the sex pilus to form a bridge between two bacteria cells; this bridge allows the F+ cell to transfer a single-stranded copy of the plasmid so that both cells contain a copy of the plasmid.
The ccd system (control of cell death) of the F plasmid encodes two proteins, the CcdB protein (101 amino acids; toxin) and the CcdA antidote (72 amino acids). The antidote prevents CcdB toxicity by forming a tight CcdA–CcdB complex. [2]
[81] [82] In large-scale microorganism processes such as fermentation, progeny cells lacking the plasmid insert often have a higher fitness than those who inherit the plasmid and can outcompete the desirable microorganisms. A toxin-antitoxin system maintains the plasmid thereby maintaining the efficiency of the industrial process. [12]
Since many R-factors contain F-plasmids, antibiotic resistance can be easily spread among a population of bacteria. [19] Also, R-factors can be taken up by "DNA pumps" in their membranes via transformation , [ 20 ] or less commonly through viral mediated transduction , [ 21 ] or via bacteriophage, although conjugation is the most common means ...
There can only be one copy of the F-plasmid in a given bacterium, either free or integrated, and bacteria that possess a copy are called F-positive or F-plus (denoted F +). Cells that lack F plasmids are called F-negative or F-minus (F −) and as such can function as recipient cells. [citation needed]
A bacterial artificial chromosome (BAC) is a DNA construct, based on a functional fertility plasmid (or F-plasmid), used for transforming and cloning in bacteria, usually E. coli. [ 1 ] [ 2 ] [ 3 ] F-plasmids play a crucial role because they contain partition genes that promote the even distribution of plasmids after bacterial cell division.
F-prime cell contains F-plasmid that integrates with the chromosomal DNA and carries part of the chromosomal DNA along with it while being excised from the chromosome. Thus F-prime plasmid is the plasmid, containing part of the chromosomal DNA which can be transferred to recipient cell, along with the plasmid during conjugation. [4]