A 189-bp repeat region within the human cytomegalovirus replication origin contains a sequence dispensable but

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Z Chen1, S Sugano, S Watanabe

  • 1The Institute of Medical Science, The University of Tokyo, Tokyo, 108, Japan.

Virology
|June 15, 1999
PubMed

Insights

The human cytomegalovirus (HCMV) replication origin requires a specific internal sequence within its 189-bp repeat region for DNA synthesis. Modifications to this sequence abolish replication, but copy number changes do not affect it.

Area of Science:

  • Virology
  • Molecular Biology
  • Genetics

Background:

  • Human cytomegalovirus (HCMV) replication origins show strain-dependent variations in the copy number of a 189-bp repeat region.
  • Previous studies indicated that a near-complete deletion of this region did not abolish origin function.

Purpose of the Study:

  • To investigate the functional significance of the 189-bp repeat region within the HCMV replication origin.
  • To determine if specific sequences within the 189-bp region are essential for HCMV DNA replication.

Main Methods:

  • Mutagenesis of the 189-bp repeat region in the HCMV replication origin.
  • Replacement of internal sequences with lambda DNA of varying lengths.
  • Introduction of nucleotide substitutions within the 152-bp internal sequence.
  • Assessing replication ability in infected cells.

Main Results:

  • Replacement of the internal 152-bp sequence or introduction of nucleotide substitutions abolished replication ability.
  • Variations in copy number (one or two copies) of the 189-bp region did not affect replication.
  • Inversion of the 152-bp internal sequence maintained wild-type replication ability.

Conclusions:

  • The 189-bp repeat region is not merely a spacer but contains an essential, irreplaceable sequence crucial for HCMV DNA replication.
  • This irreplaceable sequence likely plays a supporting role in the initiation or maintenance of HCMV DNA synthesis.

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