The DNA between Rz and cosR in bacteriophage lambda is nonessential

Area of Science:

• Molecular Biology
• Virology
• Genetic Engineering

Background:

• Phage lambda DNA contains a 2050 bp non-coding region near its right end, between the Rz gene and the cos site.
• This non-coding DNA's function and utility in genetic manipulation were not fully understood.

Purpose of the Study:

• To investigate the functional role of the non-coding DNA in phage lambda.
• To engineer a deletion (omega 1) within this region for potential applications in molecular cloning and gene expression.

Main Methods:

• Cloning of a phage lambda DNA fragment containing the non-coding region into a plasmid.
• Construction of a specific deletion, omega 1, within the cloned fragment.
• Recombination of the modified phage lambda DNA into viable phage lambda.
• Analysis of recombinant phage lambda for viability, burst size, and phage production kinetics.

Main Results:

• The omega 1 deletion recombined into viable phage lambda at a frequency comparable to the undeleted sequence.
• Recombinant phage lambda carrying the omega 1 deletion exhibited similar burst sizes and phage production kinetics to wild-type phage lambda.
• The engineered deletion did not impair phage viability or replication.

Conclusions:

• The engineered omega 1 deletion in phage lambda DNA is viable and does not affect phage production.
• This deletion provides a valuable tool for extending the capacity of phage lambda cloning vectors.
• The region can be utilized for controllable, high-level expression of inserted heterologous DNA via the lambda late promoter, p'R.