According to recently published research from South Korea, late gene mutants of bacteriophage lambda are an efficient expression vector.

“The disadvantage of a bacteriophage X expression system is that the replicated lambda DNA containing a foreign gene is coated by a phage head, and cell lysis occurs before sufficient expression of the cloned gene. The late genes of the bacteriophage X system are related to lambda DNA packaging and host cell lysis,” wrote J.S. Oh and colleagues, Seoul National University.

“This study investigated the late gene mutants of the bacteriophage X in an attempt to develop an efficient expression vector system. The bacteriophage lambda NM1070, which is a W-E- and S-mutant, had increased cell longevity due to the S-mutation. However, the genetic stability of this expression system was not high enough because the W- and E-mutation caused a defect in its re-infection.

“The bacteriophage lambda HL1, which is a Q- mutant, represses the transcription of all the late genes, even though this repression was not complete. This incomplete repression was rather beneficial to the cloned gene expression because it produced some matured phage particles, which re-infected the segregated host cell and increased the genetic stability,” wrote the researchers.

They concluded, “Therefore, a double mutant of the genes S and Q was constructed in order to exploit the merits of lambda NM1070 and lambda HL1. This lambda Q-S- mutant had higher host cell longevity and cloned gene expression than the lambda NM1070 and lambda HL1.”

Oh and colleagues published their study in Enzyme and Microbial Technology (Late gene mutants of bacteriophage lambda as an efficient expression vector. Enzyme Microb Technol, 2006;39(3):420-425).

For additional information, contact T.H. Park, Seoul National University, School of Chemical & Biological Engineering, Sillim Don San 56-1, Seoul 151744, South Korea.

The publisher’s contact information for the journal Enzyme and Microbial Technology is: Elsevier Science Inc., 360 Park Avenue South, New York, NY 10010-1710, USA.