Copyright 8 1995 by the Soriety of America

Charlotte Auerbach (1899-1994) ,r

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HARLOTTE AUERBACH,“LOTI-E” to all who knew SELMA,was the daughter of a general practitioner in C her, was born in Krefeld, , in 1899. She Jauer, Silesia. She loved poetry, literature and music died in in March, 1994. She was born into and apparently had a very lively mind. a family that was already noted for its contributions to LO-ITE was thus born into a culturedand intellectual science. Her grandfather was credited with the discov- Jewish familyon the 14th of May, 1899. A few years later ery in 1862 of “Auerbach’s plexus,” collections of nerve her family moved to Berlin where she was to grow up. fibers within the walls of the intestine supplying its mus- Her interest in biology was kindled by her father who cle layers and controlling its peristaltic movements. One took time to teach her to identify birds and plants as of the stories LOTI-Eenjoyed telling about him empha- well as the constellations in the night sky. Indeed, I sized his absorbing interest in science. It relates to remember not so long after we arrived in Edinburgh events on his honeymoon inWfirzburg. On arriving being invited to a very cold star-gazing party at Upper there he left his new wife in the hotel while he went in Gray Street when she proudly demonstrated her new search of a scientific colleague, a professor of anatomy telescope which stood mounted on its tripod in the and physiology. The discussion that followed wasso back yard ofher house. Natural history was one of her absorbing that her grandfather forgot his bride and father’s passions and heshared it with her, encouraging happily accepted a dinner invitation from the professor her curiosity and feeding her intelligence. Her interest for that evening. Later he remembered why he was in biology was not fostered in school, however, and she really in Wfirzburg and returned hurriedly to the hotel, received no formal instruction in the subject after she only to find his wife packing to returnto mother. Fortu- was 15. In spite of this she recalled an extracurricular nately, this forgetfulness was forgiven and the marriage lecture on the behavior of the chromosomes at cell was a happy one. division whichshe heard atsecondary school and which LOTTE’Sfather was a physical chemist who, himself, she described as one of her few truly spiritual experi- gained some distinction, graduating in Breslau in 1893 ences. She suddenly saw the field of biology opening and working first in the chemical industry and later in up before her and decided there and then to study it. the Ministry of Health in Berlin. In the latter position Her undergraduate years were spent, as was possible he became sufficiently senior tohave graduate students. in Germany, working in the Universities of Wfirzburg, He also did research on poisons, formaldehyde, and Freiburg and, finally, Berlin. Among her teachers dur- other agents. During this time he was initially coeditor ing this period were KNIEP, SCHLEIPand SPEMANN.In with EGG of the Handbuch o!er anorganischen Chemie 1924 she passed her Staatsexamen in biology, chemistry and later became its sole editor. LOTTE’Smother, and physics, but she doubted whether she could be

Genetics 141: 1-5 (Septemher. 1995) 2 B. J. Kilbey original and independent enough to become a good ber of whom were, like LOTTE,refugees from totalitar- scientist and decided to train as a secondary school ian European regimes. Among thepeople she teacher. In addition to her doubts about her own abili- frequently spoke of from that time were GUIDOPONTE- ties, she also was very fond of children and was anxious CORVO, PI0 KOLLERand, later, the SLIZYNSKIS (BRONIS to maintain human contacts in her work. She also real- LAW and HELENA),who were closely involved withsome ized that a Jewish woman without private means would of LOTTE’Slater work well into the 1960s. In addition stand little chance of a career in a German university. to these more permanent members, CREW also man- So, in 1924 she completed her training as a teacher and aged to attract distinguished names to give lectures or for a short time she taughtin Heidelberg andFrankfurt. to work for a few weeks. These includeJULIAN HUXLEY, This period was not very happy and it was apparent J. B. S. HALDANE and, most importantly from LOTTE’S that she suffered greatly from the anti-Semitism of the standpoint, H. J. MULLER.These were pivotal years for other members of the staff and from some of the chil- her. She became a British citizen in 1939, and this dren. This ended in 1925 when she came into a small helped her to continue with her scientific career unim- legacy and started work on a Ph.D degree in Berlin- peded while manyother foreign scholars were interned. Dahlen at the Kaiser-Wilhelm-Institut ftir Biologie un- In fact, she records that, in the same post that brought der MANGOLD, but she was unhappy with her project. the news of her new nationality, came also the letter When she suggested to her professor that she would requiring thatshe register as an alien. Two weeksbefore prefer to change direction, he said, “You are my stu- the outbreak of war in 1939 her mother joined her dent, you do as I say. What you think is of no conse- from Germany. (Her father had died of a heart attack quence!” LOTTEwas not one to compromise in such a in 1925.) L~TTE’Sposition in the Institute was ill-de- situation and, assessing her prospects in the University fined and very poorly paid, but the realization of what as unpromising, she left to take up secondary school they had escaped in Nazi Germany was compensation teaching, this time in Berlin. for the leantimes they experienced at theoutset of the In view of her later success asa teacher of undergrad- 1940s. And there were other compensations. She recalls uates, it is perhaps surprising that she did not find that HANS GAL, the distinguished Austrian composer, teaching easy. Keeping order in class exhausted her, formed an orchestra from a group of German and Aus- and the increase in anti-Semitism that permeated soci- trian refugees in which LOTTE played the cello. ety at that time probably also conspired against her. It However, the person who influenced LOTTE’Ssubse- may have been a blessing in disguise, therefore, when quent scientific development most profoundly was HER- in 1933 all Jewish secondary school teachers were sum- MAN MULLER.He came to the Institute in 1938 and marilydismissed and she was forced again to think remained until 1940. CREW told MULLERin front of about her future. She took her mother’s advice, left LOTTEthat shewould do cytological workfor him. This Germany and, with the helpof familyfriends in London drew a quick refusal from her, “No, I’m sorry. I’m no and Edinburgh, was able to join the University of Edin- good at cytology.” CREWtold her that as his assistant burgh and to complete her Ph.D at the Institute of she should do what he said, and went away. MULLER, Animal Genetics. She received the degree in 1935 in however, assured her that he only wanted people to spite of initial difficulties that arose because of incom- work on his projects who were interested in them and patibilities between the German and theBritish systems later asked her what were her interests. She replied of education and because she had misunderstood the that she was interested in gene action in development. University regulations. At first her degree was refused MULLERthen remindedher that if she wanted to under- but it emerged that this was because she had only sub- stand the gene, it would be important first to under- mitted two thesis copies, one finished and the other stand what happens when it mutates. This eventually rough, which she had assumed was simply for the re- led to a discussion of substances that might react with cords. The latter had been sent to the examiner. With the gene material and cause it to mutate, and these the help of PIO KOLLER,who was at the Institute and exchanges were to set the course of her long career. was able to make enquiries of the examiners, the whole MULLER’Sinspiration and the observations of an Ed- thing was straightened out and the degree conferred. inburgh pharmacologist, A. J. CLARK,on the similarities The subject was the development of the legs of Dro- between the pharmacology of X rays and mustard gas sophila. led LOTTEto test the ability of mustard gas to cause The next few years were difficult. LOTTEbecame per- . CLARKhad noted that thelesions produced sonal assistant to CREW.This involved cleaning cages of by mustard gas were slow to heal and tended to reap mice and budgerigars, which she quite naturally re- pear, as is the case for somatic lesions produced by X- sented, but shealso became involved in other activities rays. MULLERhad already reported the mutagenic ac- such as translation, teaching, and some research into tion of X rays, and the similarities between the lesions Mendelian genetics. The main compensation, however, caused by the twotypes of agent suggested that the was being in contact with the very lively group of work- induction of mutations might also be part of the action ers which CREWhad assembled at the Institute, a num- of mustard gas. In collaboration with J. M. ROBSON, C harlotte Auerbach Charlotte (1899-1994) 3 who had also noted this similarity, and using MULLER’S rearrange. Storage of the treated sperm increased the elegant genetic system to detect sex-linked recessive le- probability of this happening before fertilization and thals, a clear positive effect was obtained almost at once. subsequent cell division and hence made it more likely In the first experiment, which was based on approxi- that chromosome rearrangements would affect both mately the same number (> 1200) of treated and un- daughters of the dividing zygote and notbe lost as mosa- treated male chromosomes, the percentage of lethals ics. Careful cytological studies by SLIZYNSKA(see above) in the control was 0.25, whereas in the treated chromo- tested this idea: in a detailed study of smalldeficiencies, somes it was 7.7. In a later experiment the figure was she was able not only to produce evidence in support 8.6% in 790 treated chromosomes. Other agents were the interpretation but also to demonstrate that poten- also tested at this time. Vesicants such as Lewisite and tial breaks within the same chromosome tended to ma- osmic acid proved to be ineffective as , and ture together, with the result that intrachromosomal ammonia, though possibly having a weak action, failed rearrangements were more frequent than interchromo- to produce significant increases. Because the War had somal exchanges. The nature of the lesions and the started by this time and it was feared that mustard gas mechanism of the delayed effect was, however, never might beused against Britain, the results of these exper- elucidated. There was much excitement over the ele- iments could not be published until 1946. The reports gant chemical studies of PETERBROOKES and PHILLAW- were retained by the Ministry of Supply. Eventhis delay LEY on the alkylation of DNA and its enhanced and had its advantages, because LOTTEwas able to conduct extended depurination, but even these findings failed an unhurried and careful comparison of the genetic to provide a satisfactory and, more important, easily effects of alkylating agents and ionizing radiation. By testable solution to the problem. the time publication was permitted she had an impres- Another aspect of the delayed effects associated with sive corpus of observations to present to the scientific chemical mutagens that fascinated LOTTEcame from community, andon the basisof this work she was the observation that chemical mutagens appeared to awarded the prestigious degree of DSc. from the Uni- induce a gene state which could only be described as versity ofEdinburgh in 1947 and appointed a University unstable. The crucial points about these lesions, which Lecturer. In 1949 she was elected to fellowship of the she took great pains to point out, were that (a) their Royal Society of Edinburgh and in 1958 to fellowship inheritance was not unilineal-they were clearly able of the Royal Society of London. In 1958 the University to replicate as unstable lesions so that both daughter made her Reader. Her personal chair followed in 1967. cells and not only one of them received a copy of the Her comparisons between the mutagenic effects of unstable gene from the mother cell, and (b) the insta- ionizing radiations and chemicals in Drosophila occu- bility continually generated stable mutations that ap- pied much of the nexttwenty yearsand formed thebasis peared to be allelic using the rather crudegenetic crite- for her research interests to the endof her working life. ria that were then available. What was also puzzlingwas From the very first experiments it became clear that that the lesions were apparently produced mainly in chemically produced mutations, whether visibles or sex- response to mutagenic treatments, which at the time linked recessive lethals, were predominantly mosaics of made explanations based on transposing elements less mutant and non-mutant cells, whereas those induced attractive. Replicating instabilities were demonstrated by ionizing radiation were whole-body changes. Fur- for sex-linked lethal mutations in Drosophila, recessive thermore, the ratioof point mutations to chromosome lethals in Neurospora, and mutations to adenine auxo- mutations was different, being much higherafter chem- trophy in yeast cells. In the last case the consequences ical treatment than after ionizing radiation. Her thor- of instability were readily manifested as color-sectored ough knowledge of Drosophila biology was put to use colonies. However, ensuring thatthese were not anarti- to investigate this difference in a study of the effects of fact caused by the clumpingof mutant and non-mutant storing spermfrom treated males in the seminal recep- cells required greatingenuity and occupied the working tacles of the untreated females with which they were hours of many associates and visitors to the lab. ALLEN mated. Fertilization takes place only when the female JAMES and ANWARNASIM inherited the problem and is encouraged to lay her eggs, and egg laying can be studied it in Ottawa. With patience and skill with the delayed for several days under appropriate conditions micromanipulator of the sort that JAMES displayed, it of culture. Thesestudies showed that duringsperm stor- was possible to show that single cells with replicating age there was an increase in the frequency of chemically instabilities seemed indeed to exist. Some time later, induced chromosome mutations that was not matched and with some reluctance, for it was a mammoth under- by an equivalent increase in point mutations and, as a taking, JACQUI ROBERTS,working in my lab, managed result, the spectrumof mutations induced by alkylating to repeat this observation. However, not everyone was agents gradually approached thatof X rays. This finding convinced by these demonstrations and some people led to the proposal that alkylating agents produce “la- still maintained that they were artifactual, so that the tent” chromosome breaks which, in contrast to those origin of mosaic colonies remained hotly disputed for produced by ionizing radiation, take time to open and some years. If we accept that they exist, their nature 4 B. J. Kilbey has still to be finally determined and, even with the PATTERSON,was able to show that the inositol mutant availabilityof molecular techniques, this could be a allele inos37401 of Neurospora could respond positively daunting task. when induced to revert with diepoxybutane (DEB). LOTTE’Sother main interest in her later years lay in KBLMARK, GILESand others had noted that although accounting for specificity. In 1959 she was this allele reverted readily with W, it reverted poorly invited to head the MRC Research Unit in if at all with DEB and other alkylating agents. Many of Edinburgh and she embarkedwith characteristic enthu- us privately thought that this was a consequence of an siasm on the use of microorganisms for mutagenic stud- unreactive base pair at the site of the , but at ies. Her first choice was Neurospora and she was that time we had noway of demonstrating whetherthis schooled in its use by KIM ATWOOD,whom I think she was correct or not. LOTTE,in contrast, always believed failed to understand as a person but for whom she had that if she could find the right physiological conditions tremendous regard and respect. During her stay in his the inositol allele would revert or, rather, its revertants lab at the Biology Division of the Oak Ridge National would be expressed. So it was that PATTERSON wasgiven Laboratory in Tennessee, she also met and worked with the job of replacing the normal cytoplasmic environ- GUNNARKBLMARK, who, with NORMANGILES at Yale ment of the strain with the cytoplasm of the Pok~mu- and also with MOGENSWESTERGAARD in Copenhagen, tant, a strain with a respiratory defect which is cyto- had started on a study of mutagen specificity in rever- plasmic in nature and maternally inherited. When this sion experiments. At about this time the experiments was done, and to LOTTE’Sgreat delight, inositol rever- of BENZERand FREESEand of CRICK,BRENNER andother sions were recovered after DEB treatment. When the members of the Cambridge group hadlaid the molecu- normal cytoplasm was restored the allele lost its ability lar basis for mutation and for the genetic code. Impres- to respond again. sed though she was by the elucidation of the chemical LOTTEwas always very modest about her scientific nature and function of DNA as the genetic material, contributions, especially about herdiscovery of the mu- LOTTEwas unimpressed by the almost inevitable ten- tagenic effects of mustard gas. As 1 have said elsewhere, dency of workersstudying chemically induced reversion it was clear that she regarded them more as a job of to explain their observations solely in terms of events work which she had enjoyed doing. It is perhaps not taking place at the DNA level. Her earlier training en- too great an exaggeration to draw a parallel with one sured that she thought of mutagenesis as a biological of her favorite composers, J. S. BACH, who regarded process that entailed a series of events of which the himself as a competent craftsman rather than a great nucleotide change, even though essential, was only one. composer. She was also as aware asanyone of the limita- She saw observed mutagen specificities as the product tions of the work she could do. One of my own frustra- of genetic and cellular events, all of which weresubject tions was that investigation of the many documented to interference by the mutagenic treatment. These cel- phenomena could not be carried further, and I think lular events were thought of as operating at virtually it is salutary to note that many of the objectives of those every conceivable level between the exposure of a cell to initial studies of chemical mutagenesis were actually the mutagen, to the point at which the genetic change achieved in other ways. The work was undertaken origi- occurred, and afterwards in terms of the expression of nally because it was hoped that theidentification of the the altered gene. Successful expression is of particular chemicals that caused mutations would provide sorely importance for the treated auxotrophicor sensitive cell, needed information on the chemical nature of the ge- which had both to mutate and to acquire a prototroph netic partner in the reaction. Once the barrierof dem- or resistance phenotype that would allow it to survive onstrating chemical mutagenesis had been clearly over- the plating challenge confronting it. Her students and come by LOTTE’Sinitial experiments, it soon became postdocs were all set the task of finding and examining obvious that not few but many chemicals of a variety examples of the role of cellular factors in mutagenesis of classes were able to produce mutations. Chemical in whatever organism they were using. Out of this work mutagenesis was simply too blunt atool for determining came demonstrations of, for example, the role of con- the chemical nature of the gene and this was clearly stituents in the plating medium in suppressing muta- recognized by LOTTE herself. The elucidation of the tional yield specifically,the inactivation or saturation of chemical nature of the gene was achieved by totally repair processes by mutagens that acted as sensitizing different and much more directapproaches. The pleth- agents to their own action, repairspecificity at theallelic ora of mutagenic agents in fact prompted ALEXANDER level, and demonstrations that some less well-defined HOLLAENDERto raise the question of the mutagenic and probably complex cellular processes mayplay a risks from chemicals in theenvironment, and this role in determining mutational yield. Wherever the spawned the field of genetic toxicology, whichfor some search was conducted, it seemed possible to find exam- time LOTTEthrew herself into with some enthusiasm. ples of mutagen specificity attributable to events at the Mutations also played a central part in the elucidation cellular level. LOTTE’Sgreatest moment of triumph, of the genetic code, but this was achieved on the tacit however, came when an undergraduate student, HUGH assumption that the specificity of action of base ana- Charlotte Auerbach (1899-1994) 5 logues and proflavin owed nothing to cellular processes nicator of scientific ideas. Often with little more than but simply reflected events at the DNA level. It is true a short list of one-word topics to guide her, she held that recognition of the importance of cellular factors the undivided attention of successive classes of under- in determining mutation yields, repair activity, gene graduates year after year. She spoke with authority but expression, and the metabolism of promutagens, for she never minded being questioned. Unlike so many instance, is no longer a novel idea but part of the intel- of us these days, she always gave the impression of hav- lectual equipment of all those working in the field of ing all the time needed for discussion. She was not mutagenesis, but this realization probably came as always in control, however, and she used to recall with much from direct demonstrationsas from experiments some amusement the lecture in which the mice being with Neurospora. Even with these qualifications, how- used to demonstrate thegenetics of coat color escaped, ever, it is undeniable that the rapid expansion of the disconcerting audience and lecturer alike. study of gene mutation and of chemical mutagens was She stopped coming to her office in the Institute of the result of LOTTE’S initial unambiguous demonstra- Animal Genetics only after she became unable to see tion that mustard gas could alter the genes of the fruit to read, and even then she was anxious to learn what fly. Although she hated tobe described as the “mother was happening in the lab, almost envious of the new of chemical mutagenesis,” in a very real sense she was opportunities offered by molecular biology and eager and this was recognized by the conferring of honorary to hear what her erstwhile collaborators were now work- degrees from the Universities of Leiden, Dublin, Indi- ing on. In her last days she had to content herself with ana (where MULLERworked), and Cambridge, as well listening to music and literature from her tape re- as foreign memberships in the National Academies of corder. She still managed to communicate with her Science of the United States and of Denmark. friends and family abroad by phone andletter, buteven- LOTTE was a passionate believer in the importance tuallyeven that became too much. Her death came of understanding genetics. The subject fascinated her quickly and without pain. She will be remembered for and she conveyed that fascination in her lectures and her love of science, her humility, and her transparent in her books. She wrote several popular introductions honesty, but by those who knew her well she will be to genetics, some of which were translated into a wide remembered as a faithful and good friend. variety of other languages (not all of which she could BRIANJ. KILBEY read, which caused her some concern). Although she Institute of Cell and Molecular Biology had had problems with discipline in her classes as a Darwin Building, Mayfield Road teacher in Germany, she hadno problems as a commu- Edinburgh EH9 3JR, Scotland