Question

hello I need a gene that produces an enzyme that can be easily assayed for activity.

please give me at least three choices

thanks

Answer 1

A gene that produces an enzyme that can be easily assayed for activity is called reporter gene. This assayable activity can be used to report on the transcriptional activity of the desired gene. They are also known as selectable markers.

Using recombinant DNA techniques, the original promoter of the reporter gene is removed and substituted by the promoter of the desired gene. The resultant new gene is introduced into an organism and the expression of the gene of interest is observed by assaying for the product of the reporter gene.

A reporter gene favors the study of the expression of a gene for which the gene product is not known or is difficult to identify.

A common reporter gene in bacteria in bacteria is the lacZ gene from E. coli, which encodes ß-galactosidase, as a product of gene activity.

lacZ gene is also used as a marker in bacteria to identify they are naturally lac-, or they are lac- due to a mutation. lacZ gene can also be incorporated in other animal species that lack endogenous ß-galactosidase activity.

Commonly used reporter genes that produce visually identifiable characteristics produced by fluorescent and luminescent proteins. They are used in bacteria and animals include,

1. the CAT gene that encodes the enzyme called chloramphenicol acetyltransferase which confers resistance to the antibiotic chloramphenicol,
2. GFP gene that encodes the jellyfish green fluorescent protein which makes cells to glow green under blue light, and
3. luc gene that encodes the enzyme luciferase which catalyzes a reaction with luciferin to produce light in firefly.
4. lacZ is not usually a beneficial reporter gene for plants. Widely practiced reporter gene in plants is the gus A gene that encodes the enzyme ß-glucuronidase (GUS). When plant tissue is dyed with the chromogenic (color-generating) substrate X-gluc, the cells that make the GUS enzyme will turn blue. Because GUS enzyme can cleave the X-gluc and produce an insoluble blue color in those plant cells which shows GUS activity.