Name: Dr. Roger Garrett
Institution: University of Copenhagen
Location: Copenhagen, Denmark
Tell me a bit about how you came to be interested in Archaea and what your work entails.
I graduated in Chemistry at UCL London in 1964 and moved over to the MRC Biophysics Unit at KCL London to do a PhD supervised by Maurice Wilkins. Thus, apart from a few graduate courses in molecular biology, I had no formal training in biology, biochemistry, microbiology or genetics. In retrospect, despite some obvious disadvantages, this made it relatively easy to accept the hypothesis that the archaeal domain was fundamentally different from bacteria, an acceptance that was facilitated by the fact that I had also worked on ribosomal RNA sites and sequences for seven years when Fox and Woese published their seminal paper, in 1977, based on rRNA sequence analyses. Important, also, was the chemist's fascination with how cells could function at 3-5 M intracellular salt concentations or at very high temperatures (above 80oC). Thus, when I moved from an Escherichia coli translation lab in West Berlin to Aarhus, Denmark, in 1979, we focused first on molecular biological properties of haloarchaea and later, primarily through a very fruitful and enjoyable collaboration with Wolfram Zillig, switched to extreme thermophilies. Later in the ninetees (after moving to Copenhagen University) we worked on archaeal genomics and also began investigating archaeal genetic elements, primarily with Wolfram Zillig, which we pursued for more than a decade. Eventually we prioritised research on the CRISPR-Cas immune systems that are particularly diverse and complex in thermophilic archaea.
Looking back at the last 40 years, what would you describe as the most exciting areas of research linked to the study of the Archaea? And where do you see the field headed in the next decade?
The most exciting phase constituted the seminal studies, in particular on translation, initially ribosomal RNAs (Woese), the eukaryal-like transcriptional apparatus (Zillig), cell walls lacking peptidoglycan (Kandler) and ether-linked lipid membranes (Langworthy). Thereafter, followed numerous discoveries on archaea-specific cellular components and their properties and mechanisms of action, eventually underpinned by archaeal genome sequencing and analysis. There were three major archaea meetings in Munich in 1982, 1985 and 1994 where all the major archaea groups were presented, and another in Regensburg in 2005 (articles and reviews from the meeting were later published in book form - Archaea: Evolution, Physiology and Molecular Biology, eds. Garrett RA and Klenk HP, Blackwell publishing, 2007). These meetings were crucial for discussing and reviewing all the latest discoveries and hypotheses, and for planning future work in the archaea field.
Our lab. in Copenhagen invested considerable energy in characterising the genetic elements, in particular thermophilic viruses, and my colleagues in Copenhagen have continued on this since I retired. Another major general effort in the archaea field was applied to developing robust genetic systems for extremophile organisms with considerable success for Sulfolobus (She, Schleper and colleagues) and Pyrococcus (Terns and colleagues), and also for a few groups working on methanogens and extreme halophiles.
I think all these studies will continue and, in addition, there is a growing interest in exploiting archaea for biotech applications that will probably expand rapidly now that good genetic systems have been developed. However, it is also important to continue focusing on archaea-specific properties. There has been a tendency, mainly as a result of bioinformatical analyses of whole genomes, to remerge archaea and bacteria as "prokaryotes" to simplify analyses but this also seriously masks, and ignores, the archaeal- and bacterial-specific properties which are the most interesting biologically.
Participants of the Archaea meeting in Regensburg, 2005
What would you like the public (and general microbiological audience) to appreciate about Archaea?
That they are very interesting organisms in their own right with many exceptional and very interesting properties, not least the methanogens (and their significance for climate change!) Apart from the odd brief article I've written in the Danish press, I have still not seen Archaea mentioned specifically in the European or American english written press; methanogens are always "bacteria", organisms growing in Yellowstone or Icelandic solfataric fields are always "bacteria" and so on; sometimes they are referred to as "weird bacteria" but never as archaea. Thus the general public misses a very important biological story.
Are there any particular papers that you feel are absolute must reads for those that aren’t necessarily familiar with the field (and briefly, why)?
Woese, C.R., Default taxonomy: Ernst Mayr's view of the microbial world, Proc. Natl. Acad. Sci. U.S.A. 95 (19), 11043e11046 (1998)
This article summarises Woese's view of archaea. Moreover, it emphasises the importance of understanding the significance of the major differences in the informational molecular processes (in particular transcription and translation) occuring between archaea and bacteria, and the many similarities between those processes in archaea and eukarya.
Pühler, G., et al., Archaebacterial DNA-dependent RNA polymerases testify to the evolution of the eukaryotic nuclear genome. Proc. .Nat. Acad. Sci. U.S.A. 86 (12), 4569-4573 (1989)
This articles summarises all the work from the Zillig lab. performed in the early 1980's that demonstrated the major differences between the transcriptional apparatus of archaea and bacteria and the close similarities between those of archaea and eukarya.
Prangishvili, D., Forterre, P. and Garrett, R.A. Viruses of the Archaea: a unifying view. Nat. Rev. Microbiol. 4, 837-848 (2006)
This article is essentially a tribute to the early work on the characterisation of the novel and diverse archaeal viruses by Wolfram Zillig's lab. written, after his death, by three of his coworkers and collaborators. His work had a major impact on the development of the archaeal field. In an e-mail correspondence with Carl Woese, written soon after Wolfram's death, Carl confided that he had once chided Wolfram for "wasting his time" characterising archaeal viruses because he assumed they would turn out to be bacteriophage-like, but he ended his email with "but boy, was I wrong!".