In vivo splicing of protein: one continuous polypeptide from two independently functioning operons

Area of Science:

• Molecular Biology
• Genetics
• Enzymology

Background:

• The lac operon controls lactose metabolism in E. coli.
• Beta-galactosidase is a key enzyme in this pathway.
• Rec(-) merozygotes are used to study gene interactions.

Purpose of the Study:

• To investigate the unexpected formation of active beta-galactosidase from mutant genes.
• To understand the mechanism behind the synthesis of a single protein from two genes.

Main Methods:

• Analysis of active beta-galactosidase formation in specific mutant pairs within rec(-) merozygotes.
• Exclusion of genetic recombination and suppression as causative factors.

Main Results:

• Certain mutant pairs in the z gene of the lac operon produce active beta-galactosidase.
• Upon dissociation, the enzyme yields a single protomer, not two independent polypeptides.
• Genetic recombination and suppression were ruled out as explanations.

Conclusions:

• The study suggests the synthesis of a single protein from two independently functioning genes.
• This challenges conventional understanding of gene expression and protein formation.
• The findings provide novel insights into gene complementation and protein assembly.