Biotechnology and Recombinant DNA: Key Concepts and Applications

Biotechnology

the use of microorganisms, cells, or cell components to make a product

Recombinant DNA (rDNA) technology

the insertion or modification of genes to produce desired proteins

Vector

a self-replicating DNA molecule used to transport foreign DNA into a cell

Clone

population of genetically identical cells arising from one cell; each carries the vector

Cell clone containing rDNA

may be used to express (transcribe and translate) the gene of interest to produce the protein product

Example of rDNA technology

Gene for human growth hormone (hGH) has been inserted into E. coli bacteria

Selection

selecting for a naturally occurring microbe that produces a desired product

Mutation

Mutagens cause mutations that might result in a microbe with a desirable trait

Site-directed mutagenesis

a targeted and specific change in a gene

Restriction enzymes

These are enzymes in many bacteria that cut very specific sequences of DNA

Blunt ends

create blunt ends or staggered cuts known as sticky ends

Properties of Vectors

Must self-replicate, must be manipulatable, size considerations

Self-replicate

Our DNA of interest must be faithfully copied

Manipulatable

We must be able to insert, delete, site-specifically mutate genes in a vector

Size of vectors

Small vectors (plasmids) are easily manipulatable but can take smaller gene inserts; large vectors (viral vectors) can take up much larger inserts but are more difficult to manage

Shuttle vectors

exist in several different species and can move cloned sequences among various organisms

Plasmid vectors

can be used as vectors and are circular forms that protect them from destruction in recipient cells

Viral vectors

can be used as vectors and are a little more difficult to manage but can take up much larger inserts

Value of restriction enzymes

They are crucial in rDNA technology for cutting DNA at specific sequences

Criteria for a vector

Must self-replicate, must be manipulatable, must accommodate the size of the DNA insert

Use of a vector in rDNA technology

To carry new DNA into desired cells