Study reveals new information about how bacteria work

Liggins Institute research fellow Dr Justin O’Sullivan studies the structure and function of DNA within simple cells. He says an investigation, just published in the prestigious journal Nucleic Acids Research, offers new clues about how bacteria work.

Dr O’Sullivan’s team combines laboratory and computer analysis to understand how DNA is organized and reproduced within single cells such as the bacterium E coli. He says that to fit within a cell, DNA is packed into a tight ball that looks like a knotted piece of rope. Even though it is very tangled, the DNA remains open enough to allow the cell's enzymes to read the coded information it contains, repair damage and make copies.

“We investigated how DNA folds up on itself inside bacteria and how these patterns changed with different conditions. Our data shows that bacterial DNA folds in very ordered and specific ways and that changing the bacterial cell's environment results in changes to the three-dimensional arrangement of the DNA.

“Our results also show that the act of reading and copying DNA has a big effect on DNA structure’” he says.

Harmful bacteria pose a threat to human health. O’Sullivan says that in the absence of any new antibiotics becoming available, scientists need to find new ways to control the ability of bacteria to replicate themselves.

“Understanding how DNA is organized within bacterial cells and how this structure relates to function may be an important step towards finding new and very specific ways to control the spread of dangerous pathogens,” he adds.

The complex study is part of PhD student Ralph Grand’s research project and a collaboration with colleagues at the US National Cancer Institute, National Institutes of Health and Massey University’s Institute of Natural and Mathematical Sciences.

“Genome conformation capture reveals that the Escherichia coli chromosome is organized by replication and transcription”, C. Cagliero, R.S. Grand, M.B. Jones, D.J. Jin, J.M.O’Sullivan in Nucleic Acids Research, 2013.
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