Chapter 12, Problem 2AQ

Summary Introduction

To discuss:

Several genetic systems use the β-galactosidase as a reporter. The lacZ gene encodes β-galactosidase. The major advantages and disadvantages of using the luciferase or green fluorescent protein as a reporter instead of the β-galactosidase.

Concept introduction:

The lacZ gene from E. coli encodes β-galactosidase enzyme, which is required for catabolism of lactose. The cells are plated on X-gal (5-bromo4-chloro-3-indolyl-b-D-galactopyranoside) containing media. Cells expressing β-galactosidase enzyme can be analyzed by their color of the colonies. X-gal, the chemical substance is cleaved by β-galactosidase enzyme and produces blue color colonies.