Question

Explain the vector pBR 322 with a neat labeled diagram.

Answer 1

Hint: The pBR322 was known to be the first artificial cloning vector to be constructed. It is a plasmid which is a part of an extrachromosomal DNA segment, it helps in the cloning of the vector and also is important in genetic engineering.

Complete solution:
This pBR322 vector is widely used in gene cloning experiments.
In the pBR322 plasmid vector,
-p - denotes that it is a plasmid;
-BR - BR here stands for Bolivar and Rodriguez who constructed this plasmid;
-322 - It is a number that was assigned to distinguish this plasmid from others developed in the same laboratory.
Plasmid vector pBR322 is found to have around 4361 base pairs in length with the two antibiotic resistance genes that are associated with it. The two antibiotic genes are named as, the gene bla that helps in the encoding of the the ampicillin resistance (${ Amp }^{ R }$) protein, and the second is the gene tetA that helps in the encoding of the tetracycline resistance (${ Tet }^{ R }$) protein. This plasmid also constitutes the region called the origin of replication of pMB1 where the cloning starts and the rop gene that helps in the encoding of the restrictor prevents the extra plasmid copy number. There are around 40 restriction enzymes in this plasmid each having a different restriction site. Eleven of those forty sites lie within the ${ Tet }^{ R }$ gene. There are two sites in this vector for the restriction enzymes HindIII and ClaI within the promoter of the ${ Tet }^{ R }$ gene. The various plasmids are ideally constructed for the purpose of cloning and out of all of them, the most commonly and readily used is the pBR322.

Note:
In the year 1977, Herbert Boyer was the one who created the Plasmid vector pBR322 at the University of California, San Francisco in the conditions of the laboratory. The name was given after the name of two researchers Francisco Bolivar Zapata, and Raymond L. RodriguezIt, and was named after their postdoctoral research.