Direct PCR sequencing of the ndd gene of bacteriophage T4: identification of a product involved in bacterial nucleoid disruption.

The rapid disruption of the Escherichia coli nucleoid after T4 infection requires the activity of the phage-encoded ndd gene. We have genetically identified the sequence encoding ndd. Determination of the sequence of a 2.5-kb segment including ndd closed the last significant gap in the sequence of the T4 genome. This analysis was performed on PCR-amplified fragments that were purified by gel-exclusion chromatography and then submitted to linear amplification cycle sequencing. This technology permitted sequence comparison of two ndd mutants (ndd44 and ndd98) with the wild-type gene. The analysis of ndd from six bacteriophages of the T-even family indicated that the protein encoded by this nonessential gene is surprisingly conserved.