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Unraveling the genome sequence of Dublin’s own yeast species. |
Yeasts are microscopic unicellular fungi. We are all familiar with the benefits of these organisms in baking and brewing. However, similar yeast species also have the capacity to cause infections in humans. The most important causes of fungal disease are Candida species, which are well known because of diseases such as thrush (in the vagina and the mouth). Unfortunately, these species are also the cause of life-threatening bloodstream infections in a wide range of medically compromised patients, such as those with cancer and recipients of organ transplants. The most common cause of these diseases is Candida albicans. However, in 1995, Prof. Derek Sullivan and Prof. David Coleman from TCD's School of Dental Science and the Dublin Dental Hospital, in work funded by the Health Research Board, discovered a new species of Candida associated with HIV-infected and AIDS patients which they named Candida dubliniensis, after the University and City of Dublin. Subsequent research has shown that Candida dubliniensis is far less able to cause disease than its close relative C. albicans. In order to investigate why C. albicans is more virulent than C. dubliniensis, in 2005 Prof. Sullivan, Dr. Gary Moran and Prof. Coleman, who were supported by funding from Science Foundation Ireland, proposed a project to the Wellcome Trust Sanger Institute in Cambridge, UK, with the aim of deciphering the entire 14.6 million base pair C. dubliniensis genome sequence. This project has now been completed with the help of additional collaborators in the UK, the Netherlands, New Zealand and Austria, and allows comparisons to be made with the already completed C. albicans genome sequence. The results of the study have just been published online in the journal Genome Research. The data indicate that the two yeast species are very closely related (approx. 95%), but that C. albicans has specifically expanded its genetic repertoire through the expansion of certain gene families. In contrast, C. dubliniensis appears to be losing genes. "The presence of novel genes in C. albicans suggests that there are previously uncharacterised genes involved in candidal virulence" commented Prof. Sullivan. While Dr. Matt Berriman from the Wellcome Trust Sanger Institute suggests that " the results provide substantial new leads that will allow the research community to take further steps towards characterising the molecular basis of candidal virulence". Work is currently underway in the Dental School & Hospital to investigate the precise role of these genes in order to improve our understanding of how Candida species cause disease and ultimately potentially lead to the development of better diagnostic and treatment strategies. Publication details:
Comparative genomics of the fungal pathogens Candida dubliniensis and C. albicans.
Jackson AP, Gamble JA, Yeomans T, Moran GP, Saunders D, Harris D, Aslett M, Barrell JF, Butler G, Citiulo F, Coleman DC, de Groot PW, Goodwin TJ, Quail MA, McQuillan J, Munro CA, Pain A, Poulter RT, Rajandream MA, Renauld H, Spiering MJ, Tivey A, Gow NA, Barrell B, Sullivan DJ, Berriman M.
Genome Research 2009 Sep 10. [Epub ahead of print] |
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