YEAST VOL. 11: 391-392 (1995)

Obituary In Memory of Fritz M. Pohl 1939-1994

On June 7th, 1994, the European Yeast Genome Sequencing Community lost one of its most valued members. Fritz Pohl was a native of Austria, having been born in St. Johann i.P., the son of a physician. He entered the University of Graz, where he trained as a physicist from 1957 to 1963. His dissertation research, there, dealt with the microplasticity of silica- and polymer-glasses (Pohl, 1964). In many ways, this early work typi- fies the contribution which Fritz Pohl was subse- quently to make to biology. His molecular biological research was always firmly rooted in physical science and retained an intensely practical aspect such that, although he made important theoretical contributions (especially in the area of DNA structure), Fritz will probably be best re- membered for his innovations in the technology of our subject, particularly in relation to DNA se- quencing. Fritz was a strong, yet modest, character who liked to work with a small number of students rather than a large research team. He was scrupu- lous about the assignment of credit for work done in his own laboratory. Fritz allowed his students a great deal of freedom and independence, while always being generous with help and advice when this was required. Many publications from his students do not bear Fritz Pohl’s name, since he only felt co-authorship was justified when he had made some material contribution to the research.

From Graz, Fritz moved to the Max-Planck- Institut in Gottingen where he worked with Manfred Eigen. There, he first embarked on molecular biological research, using physico- chemical methods to study the structure of biologi- cal macromolcules (proteins and DNA) and investigate the conformational changes they underwent during environmental transitions. Fritz left Germany for a year (1970-1971) to work as an EMBO Fellow at the University of Bristol. His experiences in Bristol largely shaped his scientific philosophy and modus operundi for the rest of his career. Fritz liked to work in what he was kind enough to term the ‘British style’-with a small, intimate group of colleagues and placing a high premium on innovation. This period, and the time which followed his return to Gottingen, was a very $:, 1995 by .lohn Wiley & Sons Ltd

productive one. During this time, Fritz studied the salt-induced transition between the left-handed and right-handed double helical form of DNA. This work (see, for instance: Pohl, 1967; Pohl and Jovin, 1972) predicted the existence of the Z conformation of DNA which was subsequently confirmed by Alex Rich’s crystallographic analysis in 1979.

Z-DNA continued to be a focus for Fritz Pohl’s research following his move to the University of Konstanz in 1973. There, he added immunological analyses (see Pohl et a[., 1982; Pohl, 1987) to his customary physico-chemical approach (Pohl, 1986). During this time, a whole string of papers were produced by Fritz Pohl’s students (e.g. Smith et ul., 1991; Hoheisel, 1989; Baumann et ul., 1985; Richterich, 1989) on which his name does not appear and of which only few people realise or acknowledge Fritz’s contribution.

392 OBITUARY

It was with these same students that Fritz started to develop new techniques for the analysis and, particularly, the sequencing of DNA. Fritz, to- gether with Stephan Beck, developed the direct blotting procedure for DNA electrophoresis (Pohl, 1980; Beck and Pohl, 1984). It was the application of this technique to DNA sequencing, and the de- velopment of the picturesquely (and, sometimes, even less politely) named ‘bottom-wiper’, that led Fritz into large-scale DNA sequencing and into two European collaborations: on the automation of DNA sequencing with Liam Martin (Manchester Biotechnology Centre, UMIST) and Robert Massen (also at Konstanz) and, subsequently, with the European Yeast Genome Sequencing Network (led by Andrk Goffeau, University of Louvain-la- Neuve). His students have carried on this tradition of developing DNA sequencing technology: Stephan Beck in Barrell’s lab. at MRC, Cambridge, then at Milligen and, subsequently, ICRF London; Peter Richterich in Church’s lab. at Harvard and, lately, at Collaborative Research; and Jorg Hoheisel in Lehrach’s lab. at ICRF and, now, in the Genome Centre in Heidelberg; and Elmar Maier again with Lehrach in London and, now, at the Max Planck Institute in Berlin.

I remember a number of early morning swims with Fritz (sometimes accompanied by his son, Thomas) at meetings of our European Network. Fritz was a great source of strength during the chromosome 111 project; he was always confident of the project’s success and always ready with a word of encouragement or of practical advice. While being an enthusiast for the Network’s activities, Fritz did not think that this ‘cottage industry’ ap- proach to genome sequencing was sustainable in the long term, or that it was the best way of employ- ing molecular biologists whose knowledge and skills related to a particular organism. Fritz Pohl was never one for proselytising and he acted on this assertion in typical manner-finding a small-scale, innovative and highly effective solution. In 1990, Fritz (together with his three sons, Fritz, Thomas and Peter) founded a small DNA sequencing com- pany called GATC GmbH. The company under- takes contract cloning and sequencing, exploiting the ‘bottom-wiper’ technology and a colorimetric detection system (Richterich et al., 1989). GATC, under the leadership of Thomas, is the most pro- ductive sequencing lab. in our European Network (see Dujon et a/., 1994; Feldmann et al., 1994). Fritz was both pleased at having provided for his sons’ futures and proud of their achievements.

Those who have worked with Fritz are proud to have known him and will occasionally raise a glass of beer in memory to his quiet strength, his modesty, his gentle sense of humour and his non- assertive mode of leadership.

STEPHEN OLIVER

REFERENCES Pohl, F. M. (1964). Bruchfreie ritzspuren auf silikatglas

und einigen thermoplasten. Z. Ang. Phys. 18, 203. Pohl, F. M. (1967). Ein model1 der DNS-structur. Natur-

wissenschaften 54, 616. Pohl, F. M. and Jovin, T. (1972). Salt-induced cooper-

ative conformational change of a synthetic DNA: equilibrium and kinetic studies with poly (dG:dC). J. Molec. Biol. 67, 375-396.

Pohl, F. M., Thomae, R. and DiCapua, E. (1982). Antibodies to Z-DNA interact with form V-DNA. Nature 300, 545-546.

Pohl, F. M. (1980). Verfahren zur electrophoretischen trennung sowie vorrichtung dam; German Patent No. 3022 527.

Beck, S. and Pohl, F. M. (1984). DNA sequencing with direct blotting electrophoresis. EMBO J. 3,2905-2909.

Baumann, E. A., Baur, C. P., Baack, M. and Beck, S. (1 985). DNA sequence of the leftward junction in the adenovirus-simian virus 40 hybrid AD2 & D2 and determintion of the structure of the D2 T-antigen. J. Virol. 54, 882-885.

Pohl, F. M. (1986). Dynamics of the B-to-Z transition in supercoiled DNA. Proc. Nut. Acad. Sci. USA 83, 4983-4987.

Pohl, F. M. (1987). Hysteretic behaviour of a Z-DNA- antibody complex. Biophys. Chew. 26, 385-390.

Richterich, P. and Pohl, F. M. (1987). Calculation of the CD of oligo(dG-dC): influence of basic optical param- eters. Biopolymers 26, 231-250.

Richterich, P., Heller, C., Wurst, H. and Pohl, F. M. (1989). DNA sequencing with direct blotting electro- phoresis and colorimetric detection. Biotechniques 7,

Richterich, P. (1989). Non-radioactive chemical sequencing of biotin-labelled DNA. Nuc. Acids Res. 17, 2181-2186.

Hoheisel, J. D. (1989). A cassette with 7 unique restriction sites, including octanucleotide sequences: extension of multiple-cloning-site plasmids. Gene 80, 15 1-1 54.

Smith, S. B., Heller, C. and Bustamente, C. (1991). Model and computer simulations of the motion of DNA molecules during pulsed field electrophoresis. Biochemistry 30, 52645274.

Dujon, B., Pohl, F. M., Pohl, T. M. et al. (1994). Complete DNA sequence of yeast chromosome XI. Nature 369, 371-378.

Feldmann, H., Pohl, T. M. et al. (1994). Complete DNA sequence of yeast chromosome IT. EMBO J. 13,

52-59.

5795-5809.