John Sulstonの訃報を耳にして・・

今のゲノムプロジェクトの先鞭をつけたのは大腸菌であり酵母であるが、それよりやや時代が下って機能と遺伝子ゲノムの嚆矢といえばやはり線虫であろう。シドニー・ブレンナーが大腸菌をやめて次は線虫だと言い出し、このプロジェクトの中核を担ったのがサルストン、クールソンとホロビッツであった。

雌雄同体(hermaphrodite) で959個、雄(male) で1031個の体細胞の細胞が成体の線虫を構成するが、受精から二分割→4分割とその生涯の細胞系譜を追っていき959個に至るまでの系譜を完成し、逆に成体の腸のこの細胞の先祖はこの時期には「これ」、32細胞期には「これ」と先祖返りも可能にしたのがかれらの最初の功績であり、ついでレーザーを使いある時期にある細胞を潰すとその後の成体がどうなるのか、あるいは成体での突然変異体の細胞系譜とゲノム遺伝子の関連等々を体系的に調べ、ヒトのゲノム・プロジェクトに先立つこと20年前にこのような仕事をしていたのだから先駆的である。


ちなみにブレンナーの線虫突然変異体の論文は1974年である。ブレンナーの線虫プロジェクトの最初のスタッフがジョン・サルストンであるが、サルストンの細胞系譜の最初の頃の仕事はノマルスキー微分干渉顕微鏡を使い細胞を目で追うことで始まった。そこにホロビッツが加わりかれらは最初の959個の細胞系譜を完成させた。その後線虫のゲノムプロジェクトの中核も彼らは担い続けた。

小生が1992年ころ勤めていた施設にホロビッツが来ることになって、ボクは駅までホロビッツを迎えに行った。昔のことだらからボール紙に「ようこそホロビッツ様」と書いた紙を胸の前に掲げ、彼の到着を待った。繊細なヒトであり、連れていったホテルで「羊毛アレルギー」だということで寝具一式を代えさせるひと波乱があったことを昨日のように思い出す。ホロビッツはこのころ線虫変異体とその責任遺伝子の発見でnature, cellで華々しく活躍していたので、小生もこの線虫プロジェクトのことをこのころ勉強したのである。ホロビッツのと数日はとても楽しい思い出であった。

その後自分はヒトのゲノムプロジェクトに関わることをやったが、そのきっかけはどう考えてもこのときのホロビッツとの出会いであった。

テルモ生命科学芸術財団のHPより引用

2002年にブレンナー、サルストン、ホロビッツはノーベル賞を受賞するが 、この時くらいノーベル賞を誇りに思ったことはなかった。三人とも（論文でであるが）知っていた。ホロビッツとは語り合った思い出がある。このお三方はその後のゲノムプロジェクトでも中核的な働きを続けていたので、むしろ小生はゲノムプロジェクトのころのほうが恩恵・薫陶を受けていたのかもしれない。

サンガーセンターのセンター長であったが、小生にとっては「細胞系譜のサルストン」が亡くなったとの訃報である。ご冥福を祈りたい。「Cell」誌に追悼記事が載っていたので（掟破りかも知れないが）全文転記させてもらった。

Cell

Volume 173, Issue 4, p809–812, 3 May 2018

OBITUARY

John Sulston (1942–2018）

Martin ChalfieCorrespondence information about the author Martin Chalfie

John Sulston, who died on March 6, 2018, was the first speaker at the fifth International C. elegans Meeting in 1985. In his talk, John described the progress he and Alan Coulson had made toward determining the physical map of the C. elegans genome. This mapping project was very new and quite different from John’s previous work describing the complete C. elegans cell lineage. Before giving his status report, John explained why he had undertaken this new project, “I want to admit to a weakness, perhaps several. I have a weakness for grandiose, meaningless projects.” John then described his real goals: (a) to promote communication among C. elegans labs, (b) to make flanking clones of genomic DNA available to speed the molecular analysis of genes, and (c) to complete and fully connect the physical and genetic maps. Unsaid during his talk, but to my mind one of the key aspects of the success of the project, was that John was not pursuing any other studies in C. elegans; he devoted all his efforts to the mapping of the genome as both a worthwhile and meaningful endeavor and as a service to the community. These goals and his actions exemplify John’s career, which was characterized by great vision, tremendous accomplishments, and an intense belief in sharing, openness, and the development of community in science.

John is best known for three remarkable accomplishments: elucidating the complete cell lineage of C. elegans, determining the sequence of the C. elegans genome, and guiding the public effort to sequence the human genome. Those of us who worked with him and benefited from his companionship and insight also knew him to be an extraordinary person with an amazing grasp of science, a knack for designing and executing astonishing experiments, and an exceptionally strong moral concern that science be done to benefit everyone. More privately, he was a devoted and loving husband to his wife, Daphne, and father to his children, Ingrid and Adrian. For me, he was a role model not only of how to do science but also of how to be a scientist.

I first met John in 1977 at the first C. elegans Meeting at the Marine Biology Lab in Woods Hole, Massachusetts, just before I went to Cambridge for my postdoc. As I drove to the meeting, Bob Horvitz, who with John had just published the description of the postembryonic somatic lineage, suggested I talk with John about a collection of touch-insensitive mutants he had obtained and was no longer studying. John came to the meeting knowing that he was supposed to give a poster, but he decided instead to tape his slides to a window. Despite having to squint to see what was on the tiny images, I was fascinated and have worked on these mutants for the last 41 years. I am grateful and indebted to John for sharing this wonderful project, for really starting my research career.

John and Georgina Ferry described his early life, his C. elegans career, and his genome work in The Common Thread. He attributed his interest in science to a fascination with Meccano building sets and electricity, but I remember him saying that he really liked making explosives with his chemistry set. This interest in chemistry led to undergraduate and graduate degrees in chemistry at the University of Cambridge. After postdoctoral research with Leslie Orgel at the Salk Institute, John returned to Cambridge in 1969 to study C. elegansbiology in Sydney Brenner’s group at the MRC Laboratory of Molecular Biology. John’s first accomplishment, and one that continues to be of immense use to the worm community, was the development of a freezing method to store and recover worms for later use. John’s first C. elegans paper, published back-to-back with Sydney’s classic study of C. elegans genetics in 1974, was on the DNA of C. elegans, a topic on which he was destined to devote a great deal of time. Before the genome work, however, came a series of very important papers: the first study of neurotransmitters in C. elegans, the discovery of those touch-insensitive mutants, the elucidation of the cell lineage of both the hermaphrodite and male C. elegans, the analysis of mutants with defective cell lineages, the first study of the regulation of cell fate by cell-cell interactions, and the identification of the first gene affecting programmed cell death.

John’s early study of dopamine in C. elegans neurons led to the touch sensitivity research, which I later inherited, and to the analysis of the cell lineage. John identified dopaminergic cells by their formaldehyde-induced fluorescence in fixed animals and used this method to isolate mutants that failed to make dopamine. His joy at finding the first of these mutants was short lived, however, when he realized that he had already thrown out the parent plates (with the living animals needed to propagate the strains). Fortunately, he was able to retrieve the plates from the dumpster before they were incinerated. This mutagenesis was laborious, so John, noticing that cells that appeared to be mechanosensors contained dopamine, screened for mutants that were insensitive to the touch of an eyebrow hair glued to a toothpick. He found several of these mutants, but they had normal dopamine cells. A different set of neurons was affected, as I saw in those slides taped to the window at the first Worm Meeting.

The dopamine study also began John’s interest in the cell lineages. The wisdom in the field said that nematodes did not add somatic cells after hatching; they just got bigger. John, however, found that older animals had more dopaminergic neurons and more ventral nerve cord neurons than younger animals. His first lineage experiments revealed how those additional ventral cord neurons arose in the young larva. He also found that some of the newly generated postembryonic cells died soon after they appeared, providing the first description of programmed cell death in the animal.

John was an amazing experimentalist. He had the uncanny ability to simplify tasks that required both patience and intense concentration, so they seemed obvious and almost easy (for him). Early in his lineage work, he devised a simple method of mounting animals on agar pads that were topped with a coverslip with a bacterial smear so the worms could eat, move, and develop normally while he watched them grow. The entire slide could be put into the refrigerator overnight, so John could continue his observations the next morning. He documented the cell divisions in an equally simple but exceptionally clear way: cells were drawn according to a rainbow scheme depending on their location.

The embryonic lineage, however, presented new problems, principally because the embryos often flipped in the eggshell, obscuring cells that had previously been easy to see; the cells were difficult to pinpoint, and the older embryo folded into a 3-fold knot. John solved the flipping problem by inventing a reversible slide that he could turn over whenever the embryo did, and he kept track of cells by placing spider web cross hairs in his eyepieces (a trick he knew World War II bombardiers used). How he solved the 3-fold knot problem is still a mystery to me, but John did have an excellent spatial sense.

After making these improvements, John locked himself away, examined lineages four days a week (the fifth day was used for record keeping and analysis), and finished the description of the embryonic lineage in a year and a half. This work required his utmost attention. Any interruption (some, I admit, I caused) ruined the observation. John worked so diligently on the lineage that the rocking of his chair as he worked gouged a hole in the floor of his room and into the underlying concrete. (After John moved to the Sanger Center, Bob Goldstein, a postdoc in the lab, made a plaster replica of the hole, which he presented to John without comment; John took one look and said, “I know that hole.”)

Having followed the lineage of some larval cells, I knew how difficult the work was, especially since dividing cells cause a moment of panic because they are temporarily impossible to see. In comparison, the work that John was doing following cell divisions in a constantly turning and folded embryo seemed impossible to me, yet John appeared to cope easily (although he did like quiet when he was working). He further amazed me when he emerged one day from his room elated, not because he had resolved another part of the lineage but because he had solved Rubik’s Cube while working on the lineage.

John also had a terrific talent for explaining complicated ideas. I soon realized that John’s explanations always seemed to use ideas I should have learned from my introductory college courses in physics, chemistry, and biology. John, however, had obviously paid attention in those courses and had thought deeply and thoroughly about the concepts; they were integral to how he understood the world.

Most of what I learned from John, however, had nothing to do with my experiments; it was about being a scientist and a fellow human being. He thought deeply about the consequences of science and his role as a scientist. I was particularly taken by John’s fairness and lack of possessiveness when he, Bob Horvitz, and I were writing a paper in 1981 about mutant cell lineages that repeatedly made the same cells. John suggested that the extra cells had the potential to evolve to give new functions just as gene duplications could eventually lead to new gene activities. I really liked this idea, and we put it into the manuscript. Several days later, however, I found a paper that had the same speculation and felt bad when I went to show it to John. Instead of being upset that someone had beaten him to the idea, he was glad I found the paper and simply said that it must have been the source of his thought.

John was also extremely patient with me. One day, I was so excited about a result that I immediately told John about it. Unfortunately, the great result did not repeat, and I went back to John quite embarrassed and apologized for getting so excited prematurely. He wasn’t bothered and just said, “Don’t worry. I don’t believe anything you tell me until I’ve heard it three times.” I later learned that he was probably referring to the beginning of The Hunting of the Snark by Lewis Carroll, where the Bellman says, “Just the place for a Snark! I’ve said it thrice:/What I tell you three times is true.”

John’s experimental skills and ethical standards really came to the fore during his genome work. When he and Alan Coulson began studying the C. elegans genome, the standard way of characterizing DNA sequences was to make restriction maps, a process that involved many separate reactions. They, along with Sydney and Jon Karn, however, devised a relatively simple method that could characterize or “fingerprint” a DNA sequence uniquely after running the products of a series of reactions all done in a single tube in a single lane on a high-resolution acrylamide gel. This procedure not only simplified the characterization but dramatically reduced the time involved because hundreds of samples could be examined in parallel. By finding matching band sizes, they could discover overlapping clones forming what they called a contig.

The C. elegans genome project revolutionized C. elegans work. As the set of contigs increased, John and Alan offered to fingerprint clones for genetically mapped genes sent to them by anyone in the C. elegans community. These new clones were often placed within existing contigs, allowing researchers to work faster and John and Alan to connect the genetic and physical maps. As these connections grew, more people were helped because they could place genetically mapped genes into defined places in the physical map and test whether DNA in the region rescued the mutant phenotype. Many collaborations formed from this free flow of information into and out of Cambridge as members of one lab realized they were cloning genes that another lab was studying genetically. As John said at the 1985 Worm Meeting, this community building, which he called “genomic communication,” was one of the main goals of the project.

John and Alan were joined by Bob Waterston, who introduced the use of yeast artificial chromosomes to connect the contigs, and two sites, one in Cambridge and subsequently in Hinxton (the Sanger Centre, now the Sanger Institute) led by John and a second at Washington University in St. Louis led by Bob, were established. As the contigs came together, Bob and John were eager to begin sequencing the C. elegans genome. They reasoned that with the largest characterized physical map, C. elegans provided the best test case for the upcoming human genome project. They received funding for a pilot project to see whether large scale sequencing was feasible.

John realized that this pilot stage and subsequent sequencing needed a larger, more efficient enterprise that was more like a modified assembly line with each person contributing to a specific step than a standard laboratory. One particular need in this enlarged effort was for people who could accurately input sequence data. John found these people in a unique but characteristic way: he went to the local supermarket, noted which cashiers were the quickest and most accurate, and asked them if they would like to use their skills in a scientific enterprise. Knowing John, I suspect he also paid them more money. The successful completion of this initial phase led to funding to finish the sequence, which was published in 1998, making C. elegans the first animal to have its entire genome sequenced.

The success of the C. elegans pilot phase also convinced John and Bob that the human-sequencing project should begin, even though others thought that the project was premature. Their enthusiasm and expertise soon initiated the public effort to sequence the human genome. At this time (1992), John and Bob were tempted to join a private sequencing effort because it would provide sufficient funding to complete the project, something that funding agencies were balking at. In considering this offer, John and Bob insisted (as they would for the public effort) that the C. elegans genome had to be completed and that all the human sequence data had to be publicly released daily. This flirtation with private funding was short-lived, in part, John confided to me, because one of the members of the proposed scientific advisory board was so disruptive that John considered him to be a dominant negative for the entire project (it was the first time I had heard this genetic term used to describe someone, but it was very appropriate).

The subsequent public effort by the International Human Genome Consortium flourished under John, Bob, and Eric Lander’s leadership of the three major sequencing centers, and a first analysis of the draft sequence of the human genome (all of which had been made available online) was published in 2001. Rather than stop with the draft sequence, the public effort refined the sequence over the next three years. The sequencing of the human genome stands out as one of the monumental achievements of 20th-century science. Our world has been permanently altered by what they learned.

To the lay public, however, the most interesting aspect of the Human Genome Project was the apparent rivalry between the public effort and the private effort mounted by the biotech company Celera. John’s perspective on these two efforts appear in The Common Thread (I particular enjoy his description of a press release that said nothing technically wrong, but which was entirely misleading) and in two commentaries he wrote with Bob Waterston and Eric Lander.

John garnered multiple honors for his work: he became a Fellow of the Royal Society, was knighted and later made a Companion of Honor, and received several scientific awards and prizes, including the 2002 Nobel Prize in Medicine or Physiology, which he shared with Sydney Brenner and Bob Horvitz. One of the more unusual honors, Mark Quinn’s portrait of John, consisting of bacterial colonies carrying his DNA, is now found in London’s National Portrait Gallery in London. A more dubious distinction occurred inugust of 2005. In an article entitled “Evangelical Scientists Refute Gravity with New ‘Intelligent Falling’ Theory,” The Onion featured a picture of John claiming he was Rev. Gabriel Burdett from the Evangelical Center for Faith-Based Reasoning. I suppose they used his picture because they thought with his white beard and white hair, he looked almost biblical (ironic for someone who did not believe in religion). And John continues to make his mark on popular culture; in the recently released science fiction film Annihilation, a student runs up to her biology professor (Natalie Portman) and says, “I read the John Sulston paper last night.”

John accepted honors not because he cared about the praise but because he wanted to use their cachet for a new career following the Nobel Prize. Specifically, John became a spokesperson for the open and free use of scientific information and for human rights more generally. He became the Chair of the Institute for Science, Ethics, and Innovation at the University of Manchester; served on the Human Genetics Commission in the United Kingdom, the Committee on Freedom in the Conduct of Science of the International Council for Science, and the Israeli-Palestinian Science Organization; and was an important advocate urging the Royal Society to join the International Human Rights Network of Academies and Scholarly Societies. In his new role as a public humanist, he wrote about the fair and open use of genetic sequence information, genetic equity, the danger of patents on biological information and on organisms with synthesized genomes, and the role of science in promoting global development.

I have tried in this brief overview of John Sulston’s life to give not only a summary of his astonishing scientific contributions but also a glimpse of why those of us who knew him viewed him as one of the most remarkable people we have ever known. I find this latter part the most difficult to express: how much we miss his joy of science, his sage counsel, and his exuberant pleasure in life. Lately, I have been reminded about seeing him riding his old bicycle to and from the lab, sharing a pint with him at the Frank Lee or the Green Man in Grantchester (he often bought the first round), and learning that when he discovered that Freestones Bakery, makers of a loaf of bread called a cobber that was so good you bought two because you knew you would finish one by the time you got home, was going out of business, he bought out the store and stashed the loaves in his freezer. And I miss his smile. When he was happy, which was often, he beamed.

Acknowledgments

No single person can adequately summarize another’s life, so I am grateful to the many friends who commented on the manuscript and shared their stories with me: Donna Albertson, Carol Corillon, Alan Coulson, Bob Goldstein, Jonathan Hodgkin, Bob Horvitz, Patty Kuwabara, Jim Priess, Bob Waterston, and John White.