Formal Lab report (Genetics-Operon Fusion) Bio.

Operon Fusions

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Introduction Experiment : Selection for ara-lac operon fusions on MacConkey media

Abstract

Specialized transuding phage Mud1 (lac , bla )containing a gene encoding for ampicillin resistance and the lac structural genes lacking the promoter was constructed by recombinant DNA and used to transform MC4100 strain of E .coli . Transposition of the Mud1 (lac , bla ) phage to chromosomal sequences resulted in lac expression being controlled by chromosomal promoter of the bacteria and mutation of the arabinose genes if the insertion was

in the arabinose operon (Casadaban and Cohen 1979 ) Selection for transformed MC4100 in general was done by selection for ampicillin resistance on media containing ampicillin .Only transformed bacteria survived in the presence of ampicillin .Selection for arabinose resistance was done on media containing arabinose . The patching of the ara-lac fusions on the appropriate media gave information on the mode of regulation of lac genes and the specific point of insertion of the phage bearing the lac gene within the arabinose operon . Fraction of ara :Mud1 insertions lysogens were determined by plating ara-lac fusions on different plates and incubated The phenotypes of the colonies selected were determined the information was utilized in determination of the specific point of insertion of the phage within the arabinose operon

Introduction

In this experiment a transducing phage Mud1 carrying bla (for ampicillin resistance ) and lac structural genes without a promoter (reporter genes was used to transform MC4100 bacterial strain and selection for ara-lac operon fusions carried out on appropriate...