Whipplei genome

19 February 2003

Researchers at the Wellcome Trust Sanger Institute in Cambridgeshire, and colleagues in the UK, the USA and Germany, have sequenced the genome of the potentially deadly bacterium Tropheryma whipplei.

T. whipplei lives in the lining of the gut, causing weight loss, diarrhoea and abdominal pain. Over long periods it can give rise to Whipple's disease, which can cause severe heart disease or neurologic disease and is difficult to diagnose.

The organism is remarkably small: its genome consists of just 926 000 base pairs, containing a predicted 784 genes, while most bacterial genomes are three to four times as large and typically code for 3000 or so genes.

Despite its small size, T. whipplei is adept at evading host responses. Within its compact genome, T. whipplei seems to have packed a sophisticated array of tools to escape our defence mechanisms. As well as swiftly changing its own proteins to elude the human defence system, the organism also appears to cloak itself in membranes stripped from the host cells, further reducing its appearance as a foreign invader.

Since T. whipplei is very difficult to grow in the laboratory, its genome sequence is the best 'microscope' through which to study this remarkable organism. This research will also shed light on how other bacteria survive, evolve and proliferate. The genome sequence will also facilitate the development of new diagnostic tools. The sequence will be published in the 22 February issue of the Lancet.

Whipplei genome

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