RNA Splicing at 40: Reflections on Scientific Progress, Policy, and Social Justice

Lessons from our session at AAAS-2017, held on 2-18-2017; Session organizer: Pnina G. Abir-Am/WSRC-Brandeis; Session co-organizer: William C. Summers/Yale.

by Dr. Pnina G. Abir-Am, Resident Scholar, WSRC, Brandeis University,(pninaga@brandeis.edu)

The discovery of RNA splicing (1977), a landmark in the history of molecular biology and just as important as the announcement of DNA’s structure (1953) and messenger-RNA function (1961), marks its 40th anniversary this year. The discovery poses major challenges for historians of science, as the session’s subtitle suggests, on the interaction of scientific progress, social justice, and science policy. Scientific anniversaries have already engaged historians of science due to their unique ways of illuminating the nexus of “history and memory.” (For example, two dozen historians of science from several countries contributed to Commemorative Practices in Science: Historical Perspectives on the Politics of Collective Memory. (University of Chicago Press, 2000; vol. 14 of Osiris, annual publication of the History of Science Society) Eds.: Pnina G. Abir-Am & Clark A. Elliott; La Mise en Memoire de la Science, (Paris: Editions des Archives Contemporaines, 1998) sous la direction de Pnina G. Abir-Am. Contrary to “received wisdom” these volumes are not a translation of each other (i.e. the authors are different in each volume except for three who wrote different essays for each volume).) Since previous sessions on anniversaries of the discovery of DNA structure did very well at the HSS Annual Meetings in 2003 and 2013; it seemed worthwhile to plan a session at AAAS on the 40th anniversary of RNA splicing, and to make it a collaboration between scientists, especially those whose perspectives are not well known, and historians of science.

Co-sponsored by Section L (History and Philosophy of Science) of AAAS, our session consisted of three speakers (Pnina Abir-Am, Louise Chow, and Ruth Sperling), a moderator (William Summers), and a discussant (Thomas Broker). Summers opened the session by explaining the nature of the discovery of RNA splicing. (By showing that many eukaryotic messenger-RNAs are not co-linear with DNA but rather are products of (multiple) splicing of non-contiguous segments of a primary transcript of the genome, the discovery not only challenged the universality of RNA-DNA co-linearity but led to a new paradigm of genetic regulation. Complex RNA processing mechanisms, such as splicing but especially “alternative splicing” enable a relatively small number of genes (~20K) to code for a much larger diversity of functional proteins. (>150K) For further details see M. Fry, (2016) Landmark Experiments in Molecular Biology, Elsevier; especially ch. 11, “The Surprising Discovery of Split Genes or RNA Splicing,” 481-521.) The discovery, which came as a much emphasized “surprise,” (note 3) opened a new vista not only in basic molecular biology, but also in its far-reaching applications for the Human Genome Project and the biotech industry. The discovery culminated with recent achievements of uncovering high resolution structures of intermediates of the biomolecular assembly in charge of splicing: the spliceosome. The structural and functional studies of the endogenous spliceosome—the supraspliceosome—a huge (21 Mda) standalone biomolecular machine in nature (bigger than the ribosome!) were also presented in our session.

Prior to introducing the speakers, Summers further emphasized scientific, historical, philosophical, and sociological issues converging around the theme of scientific credit, further elaborating on why the discovery of RNA splicing is an excellent example of a problematic allocation of credit. For example, as Summers reminded the audience, most of the discovery’s co-authors, including the first authors, received no significant credit for their innovative work (The Nobel Prize was given in 1993 to two lab directors, Richard Roberts & Philip Sharp; as a result, scientists widely assume that those two were the primary and only discoverers. (e.g. Fry 2016 in note 3) However, recent interviews with scientists revealed that they are aware that the clinching work was done by those who “did not get the Nobel” (see details in note 7)). In some cases, the names, let alone the career trajectories of the first authors, are barely known. Our session’s aim, as the first effort by scientists and historians to shed light on this discovery, was therefore to explore whether the role of some scientist-discoverers may have been obscured, as the canonical account of this key discovery has evolved during the preceding four decades. (Note 3)

The connection between the moderator’s introduction of the challenges surrounding scientific credit for discoveries in general— and for RNA splicing in particular—and the speakers, thus became obvious. Louise T. Chow, Professor of Molecular Biology at the University of Alabama in Birmingham, explained in stunning detail—further captured by superb slides—her training in advanced electron microscopy of viruses and nucleic acids as a graduate student and as a postdoc, working with Norman Davidson (On Davidson, see his biographical memoir as a member of the US National Academy of Science, https://www.nap.edu/read/11429/chapter/5; though well known in his own right, Davidson was a key collaborator of Linus Pauling’s, as evident from his role as co-custodian of Pauling’s public memory. See A. Rich & N. Davidson, eds. Structural Chemistry and Molecular Biology (honoring Pauling’s 65th birthday, San Francisco: Freeman, 1968. On Pauling’s students who contributed to molecular biology see P.G. Abir-Am, “Pauling’s Boys and the Mystery of DNA Structure,” in M. Kaji, Y. Furukawa, H. Tanaka, and Y. Kikuchi, eds. The Transformation of Chemistry from the 1920 to the 1960s, (Tokyo: The Japanese Society for the History of Chemistry, 2016) 99-112. Online version at http://kagakushi.org/iwhc-2015)  at Caltech. To that training, contained in a particularly sophisticated PhD thesis, she added method improvements devised during her time as a junior staff scientist in the Electron Microscopy (EM) lab at the Cold Spring Harbor Laboratory (hereafter CSHL), as well as her special flair for the EM technology. Such an edge enabled her to convert the EM technology, which many scientists at the time (including her would be collaborators) regarded as a mere “service” or confirmation tool, into a discovery tool. Chow thus redefined the discovery (from its initial origins as an effort to clarify findings from other fields, such as the chemistry of oligonucleotides, RNA-DNA hybridization, and gene transcription) into an EM discovery, the centerpiece and proof of RNA splicing as a “surprise” discovery (Chow, L.T., Gelinas, R.E., Broker, T.R, Roberts, R.J. (1977) “An amazing sequence arrangement at the 5’ ends of adenovirus 2 messenger RNA”, Cell 12(1): 1-8. The paper was a collaboration between two labs, the Electron Microscopy Lab (Broker & Chow) and the Nucleic Acids Chemistry Lab (Gelinas & Roberts). Broker & Roberts had been Chiefs of their respective labs for the preceding two & five years, respectively. Chow was a staff scientist in Broker’s EM lab and Gelinas was a 2nd year post-doc in Roberts’ Nucleic Acid Chemistry lab. Chow’s inventiveness in applying advanced electron microscopy techniques to the precise mapping of several loops on the adenovirus genome away from the sites which code for the main mRNA, was documented by her in great detail. Chow et al. 1977 is cited in the scientific literature as one of two “discovery papers.” The other cited paper is Berget,S.M, C. Moore, P.A. Sharp, (1977) “Spliced segments at the 5’ terminus of adenovirus 2 late mRNA,” PNAS, 74, August 1977, 3171-5. Roberts and Sharp shared the 1993 Nobel Prize (note 5). Other CSHL authors published a total of three supportive papers, which directly followed Chow’s et al. in the same issue. The role of the other teams remains the subject of parallel historical research. One of my students who participates in such research as part of a Student-Scholar Partnership (SSP) at Brandeis University also attended our session). Chow went on to discover “alternative splicing,” a process of even greater importance than ordinary splicing. However, she remains unrecognized for either discovery.

Session discussant Thomas R. Broker, also of the University of Alabama in Birmingham, who is the 3rd co-author of the “discovery paper” from CSHL, was at the time (1977) the Electron Microscopy (EM) Lab Chief at CSHL and worked closely with Chow on the challenge of accurately mapping the DNA loops formed whenever RNA-DNA hybridization included non-hybridizing segments (under certain conditions, RNA-DNA hybrids are more stable than double stranded DNA, so non-hybridizing DNA segments form loops visible in the EM). These two arrived at CSHL in February 1975, shortly after they had met and married during their time as post-docs in Davidson’s lab at Caltech. At the organizers’ request, Broker elaborated on how Chow’s role as discoverer has been overshadowed. He suggested that the position of one of their two collaborators, Richard Roberts, as the last co-author (a position often associated with lab directors), his prepublication disclosures of Chow’s “amazing” findings to selected colleagues outside CSHL, and, one might add, Roberts’ initial understanding of the discovery as a”mere” outcome of his and Gelinas’ efforts to confirm an hypothesis on the origins of an unusual “cap” structure uncovered by Gelinas, helped obscure the key role of the EM scientists in general, and that of first author Louise Chow, in particular (notes 6 & 4) ((Among them a disclosure at a Gordon conference in 1977, as shown in Abir-Am’s presentation that quoted a scientist who attended that conference.) Indeed, many scientists still believe that all four co-authors (note 6) worked in a lab headed by Roberts and were his subordinates (This confusion persists even though Roberts and Gelinas never worked in electron microscopy at that time. At a meeting held at CSHL on 10 Aug 2014, Roberts acknowledged before an audience, which included RNA splicing workers, as well as several historians, myself included, that the discovery revolved around its electron microscopy findings, which were presented there by Louise Chow.) In reality, Broker and Chow were independent scientists from another lab who brought unique and definitive expertise to the collaboration. In fact, Gelinas & Roberts approached Broker and Chow in the first place because they needed new input to solve their problem. To sum up, Broker and Chow were equal partners in a collaboration that needed different forms of expertise from different labs, yet their key role became blurred, especially outside CSHL, where Roberts had more opportunities to share his own perspective on this collaboration (Richard Gelinas, a post-doc in Roberts’ lab, prepared the nucleic acid fragments used in Louise Chow’s sophisticated electron microscopy experiments, and it was he who suggested to Roberts that they seek Broker’s and Chow’s help with the EM. As Chow emphasized, yet another CSHL scientist, J. Lewis, provided them with “leftover” mRNA without seeking co-authorship.)

Speaker (and session organizer) Pnina G. Abir-Am then argued that the problematic allocation of scientific credit in the case of the discovery of RNA splicing stemmed from an even wider range of factors, both scientific and social-political, extending well beyond communication and publication issues. She suggested that the power relations prevailing in science at the time may have also been responsible for overlooking Chow’s role as discoverer. Having studied research schools of molecular biology in the US, UK, and France as transgenerational and transnational arenas, Abir-Am drew attention to the vulnerability of some scientists (in particular junior, women, and foreign scientists) when scientific credit is awarded. She further highlighted the role of intersectionality in magnifying such a vulnerability in the specific case of Louise Chow for whom gender, ethnicity, and rank, (i.e. being a junior Chinese immigrant woman scientist) converged to obscure her role as discoverer (Pnina G. Abir-Am, “Molecular biology in the context of British, French, and American cultures” in Sciences and Cultures, issue, no. 168, of International Social Science Journal, Ed. H. Vessuri, June 2001, 187-199, (translated by UNESCO into its official languages including French, Spanish, & Chinese)). In this case, the role of ethnicity is not limited to Chow’s East Asian looks but also to her cultural heritage in Confucian philosophy, which instilled in her the belief that one’s work should speak for itself.

1978 CSH Symposium

Louise Chow & Thomas Broker at a Cold Spring Harbor Laboratory Meeting in 1978; Franklin Stahl of the “Meselson-Stahl experiment” can be seen in the background.

Despite significant improvements in the position of junior, women, and foreign scientists in the last four decades, there is still reluctance to accept these individuals as discoverers, as if somehow such categories remain particularistic and therefore less suitable than the traditional category of senior men, who seem to represent the much emphasized universality of science (For the complex discourse of particularism and universalism in democratic polities see M. Samuels, The Right to Difference, (University of Chicago Press, 2016).) Abir-Am also raised the issue of how “science policy in the service of society”—the theme of the AAAS-2017 meeting—might be deployed to secure social justice in the allocation of scientific credit. For example, accepted practices in the scientific community could be reframed so as to require that prize committees consult all co-authors of discovery papers, not only lab directors, especially those who enjoy the patronage of power brokers (For example, the literature on RNA splicing suggests that the Nobel co-laureates Roberts and Sharp (notes 5 & 7) benefitted from lobbying by J.D. Watson and D. Baltimore, respectively, who were among the most powerful scientists in the US and elsewhere.)

Abir-Am also dwelled on the parallel predicaments of junior and foreign scientists, whether male or female. As evidence that some junior scientists are perfectly capable of contributing to discoveries, she pointed out that in the last decade or so, several junior scientists were included in Nobel Prizes (e.g. Aaron Chehanover in 2004; Carol Greider in 2009).

Abir-Am then raised the issue of the invisibility of foreign scientists working outside the US, to the effect that groups from France (Breathnach, Mandel & Chambon) and Israel (Aloni, Bratosin, Horowitz, & Laub; and Lavi & Groner) which also published on RNA splicing in 1977, are almost unknown in the US (Aloni, Y., R Dhar, O Laub, M. Horowitz, G. Khoury, “Novel mechanism of RNA maturation: The leader sequences of SV40 mRNA are not transcribed adjacent to the coding sequences,” PNAS, v. 74 (9) September 1977, 3686-9; Aloni, Y., S. Bratosin, R. Dhar, O. Laub, G. Khoury, (1978) Cold Spring Harbor Laboratory Annual Symposium (this team includes three Israeli scientists as authors 1, 3, & 4, and a technician as author 2 in the second paper, all from the Weizmann Institute in Rehovot). Breathnach, R., Mandell, J-L, and P. Chambon, (1977) “Ovalbumin gene is split in chicken DNA,” Nature, 270, 314-319; (24 November) this team is composed of French scientists from the University of Strasbourg; Lavi, S. and Y. Groner (1997) “5’ Terminal Sequences and coding region of late SV40 mRNAs are derived from non-contiguous segments of the viral genome,” PNAS, 74, 12, 5323-7. (This team is made of two Israeli scientists working at the time at the Weizmann Institute).) Given the condensed session format, this issue could not receive the attention it deserves, though luckily it was highlighted by the President of the Royal Society at another AAAS event that day.

The final speaker, Ruth Sperling of the Hebrew University in Jerusalem, a former Chair of its Genetics Department, faced a dual task. On the one hand she described the above mentioned two teams of Israeli scientists (note 13), whom she knew at the Weizmann Institute in the 1970s, and situated this discussion in the context of a “journal club on chromatin and gene expression” she herself had organized there. The discovery of split genes inspired her to shift her own research from chromatin to the RNA splicing machinery. She then detailed the significance of alternative splicing and the recent achievements in the field in uncovering high resolution structures of spliceosome intermediates by cryo-EM. She further presented functional and structural studies of the endogenous spliceosome—the supraspliceosome—in her own work, recently published in January 2017, and featured on the cover of WIRES RNA journal (Sperling, R. (2017) “The Nuts and Bolts of the Endogenous Spliceosome,” WIRES RNA, vol. 8,no. 1, January/February 2017. DOI: 10.1002/wrna.1377. In 1979, Ruth and her partner Yossi Sperling left for a sabbatical at Stanford (in the lab of Roger Kornberg, a 2006 Nobel Laureate who solved the structure of RNA polymerase at high resolution) so as to switch their efforts to the RNA splicing machinery. We were delighted that Ruth was able to join our session from far away Jerusalem, especially in view of Yossi’s recent death. HSS members familiar with Creative Couples in the Sciences would be particularly gratified to learn of these amazing collaborative couples in our session.)

The supraspliceosome, composed of four spliceosomes connected by the pre-mRNA, is a general stand-alone complete macromolecular machine capable of performing splicing, alternative splicing, and all the nuclear processing activities that the pre-mRNA has to undergo before it can exit from the nucleus to the cytoplasm to encode for proteins. Sperling’s team is seeking to achieve high resolution of the supraspliceosome structure, taking
advantage of the most recent revolution in cryo-EM.

Our session was well attended by a diverse audience of scientists (junior and senior), women and men, outsiders to Boston, local fixtures (among them a former President of MIT and a current Harvard University Press Editor), a hard working AAAS photographer, and one of my SSP students who benefitted from AAAS’s graciousness with guest badges. As befits a “lucky” session, (i.e. one that required a great deal of work!) even the weather rose to the occasion changing from snowy & freezing two days earlier to 50 degrees on February 18!

When the lively Q&A ended, our absorbing conversations continued unabated, first at a Legal Seafood lunch, and later at the UK Research Councils’ reception on the Prudential’s Skywalk. Against a great view of Boston at night, and the taste of New England chowder, lobster mini-sandwiches, and a decent choice of drinks, we finally concluded our long day with a moving speech by the President of the Royal Society. An Indian born US citizen and a 2009 Nobel co-laureate for his share in the solution of the ribosome structure, Venki Ramakrishnan’s presence exemplified the centrality of both women and foreign scientists: one of his Nobel colaureates, Ada Yonath, was a classmate of Ruth Sperling; Ramakrishnan and Yonath played a key role in solving the structure of a very large element of the biomolecular machinery, the ribosome; Sperling is working on the structure of an even larger biomolecular machine: the supraspliceosome.

This AAAS meeting provided a welcome opportunity for historians of science to interact with scientists to discuss topics of mutual interest, especially contemporary issues related to social justice in the practice of science and the important contributions that historians of science can provide. As historians of science, we use our archival and other skills not only for illuminating the intellectual origins of scientific discoveries, but also in the service of restoring social justice in the allocation of scientific credit. As our session has amply demonstrated, the time has come to abandon a trio of outdated biases—paternalism, sexism, and chauvinism—which have long obscured the key role of junior, women, and foreign scientists in scientific discovery. It is hoped that the case of RNA splicing, with its similarities to the better-known cases of DNA’s structure and HIV, (where it took decades to recognize the key roles of Rosalind Franklin and Francoise Barre-Sinoussi, respectively) those who have long encountered epistemic injustice will be given proper credit for their critical roles in scientific discovery.