![]() Three genes that encode the digestive enzymes involved in breaking down arabinose ( araB, araA, and araD) are clustered together in arabinose operon 3, and all depend on initiation of transcription from a single promoter, pBAD. The bacterial genes encoding the enzymes needed to metabolize the simple sugar arabinose are a perfect example. These clusters of genes controlled by a single promoter are called operons. In bacteria, groups of related genes are often clustered together and transcribed into RNA from one promoter. Regulation often occurs at the level of transcription from DNA into RNA, specifically at the promoter, where RNA polymerase binds the DNA and begins transcription of the gene. Gene expression is carefully regulated to allow organisms to adapt to differing conditions and prevent wasteful production of proteins. Multiple cloning site - a region containing restriction sites (NdeI, HindIII, EcoRI, etc.), sequences that permit the insertion or deletion of a gene of interestīacteria transformed with the pGLO plasmid are selected by ampicillin resistance and when induced to express GFP, they glow fluorescent green under UV light!.araC - gene that encodes the regulatory protein that binds to the pBAD promoter only when arabinose binds to the AraC protein is the production of GFP switched on.pBAD promoter - binds AraC-arabinose and promotes RNA polymerase binding and transcription of the GFP gene. ![]() bla - gene that encodes β-lactamase, an enzyme that breaks down the antibiotic ampicillin transformants expressing the bla gene can be selected by placing ampicillin in the growth medium.ori - origin of pGLO plasmid DNA replication (essential for making more copies of the plasmid).GFP - jellyfish gene that encodes green fluorescent protein (GFP).The essential sequences include the following: Bio-Rad’s pGLO plasmid contains DNA sequences that enable its replication and expression of the fluorescent trait (phenotype) in bacteria following transformation.
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