In keeping with the growing movement in scientific publishing toward transparency in data and methods, we propose changes to journal authorship policies and procedures to provide insight into which author is responsible for which contributions, better assurance that the list is complete, and clearly articulated standards to justify earning authorship credit. To accomplish these goals, we recommend that journals adopt common and transparent standards for authorship, outline responsibilities for corresponding authors, adopt the Contributor Roles Taxonomy (CRediT) (docs.casrai.org/CRediT) methodology for attributing contributions, include this information in article metadata, and require authors to use the ORCID persistent digital identifier (https://orcid.org). Additionally, we recommend that universities and research institutions articulate expectations about author roles and responsibilities to provide a point of common understanding for discussion of authorship across research teams. Furthermore, we propose that funding agencies adopt the ORCID identifier and accept the CRediT taxonomy. We encourage scientific societies to further authorship transparency by signing on to these recommendations and promoting them through their meetings and publications programs.

As a complement or appendix to the printed article, supplemental material represents a powerful advantage of online publishing, allowing authors to present supporting evidence, such as movies and large data sets, that cannot be included within printed journal pages. Unfortunately, over the years supplemental material has evolved into a seemingly limitless repository for additional "stuff": a wide range of control experiments, preliminary next-step experiments, data responding to specific reviewers' concerns, results that just "don't fit" within the main paper, extended discussions, and methodological details. It has become a mechanism for expanding the overall content of a paper without any delineated change in editorial standards. In some cases where length limits are particularly strict, even major points in the paper can be based on experiments that only appear in the supplement. Although this rapid expansion of supplemental material may provide a sense of increased rigor and appear cost-free in the age of online publishing, it has many drawbacks for authors, reviewers, and readers. Authors often feel compelled, by their own desire to be comprehensive and in response to questions raised in the review process, to include increasingly large amounts of data that exceed the traditional restrictions of the printed article. Reviewers may feel responsible, as the supplemental material is ultimately published as part of the peer-reviewed publication, to assess this information with the same attention and standards as the main body of the article, which often means that they are asked to evaluate the equivalent of two papers in the place of one. And readers may find it difficult to navigate through large supplements and may be unsure about how carefully the supplemental material was evaluated in the review process. As with the paper itself, which has over time evolved a reasonably agreed upon standard and structure, it seems time to begin to define a similarly accepted standard for supplemental material. This month, we are rolling out across Cell Press new author guidelines for Supplemental Information, and we hope that they will help to provide a framework and standard for evaluating, accessing, and communicating information that stands in support of the main text and figures. One of the first issues we confronted in thinking about structuring supplemental material was one of setting limits. Limits of course have both positives and negatives. On the plus side, it seems in the best interest of everyone in the scientific community that the concept of a "publishable story" be at least roughly defined. A downside of length limits is that they don't have a conceptual basis—they aren't about the science. After much discussion and debate, both within our editorial group and with scientists, strict overall length limits struck us as somewhat arbitrary, and we instead focused on a more conceptual organization. In considering what would be most appropriate to include in supplemental material, we came away from these discussions with three major conceptual categories. One is evidence that provides deeper support for the points made in the main paper; another is large data sets and multimedia that can only be presented online; and a third is detailed information about the methods. We also believe that the main paper should provide a clear and compelling presentation of a scientific discovery that is sufficiently streamlined to be readily accessible to nonexperts, whereas the Supplemental Information can provide information in greater depth for aficionados and those actively looking to repeat and build on the experiments presented. This overall conceptual framework forms the basis for our new guidelines, in which each item of supplemental data (including display data, tables, and movies) will be specifically associated with a figure or table in the main paper and will be supportive of the main conceptual point of that figure or table. In addition, all of the pieces of supplemental data associated with a main figure will be organized into a single, easy-to-navigate figure. We believe that this organization will enable a clearer integration of the information in the supplement with the information in the main paper and facilitate more fluid navigation between the two. It will also point the experts to the additional supporting information relating to a particular experiment while allowing more general readers to absorb the take-home message without being overwhelmed by additional details. Finally, by limiting supplemental data to only those that directly support a point made in one of the main figures, preliminary data that attempt to extend the scope of a paper would be excluded. We hope that this new framework will make it easier for authors to decide what to present in the main paper, what to include in the supplement, and what not to show at all. Our overall aim is to make it more straightforward for everyone involved in the publication process—authors, reviewers, editors, and readers—to organize, evaluate, navigate, and use the Supplemental Information associated with a published paper. This new organization of Supplemental Information will also mesh with forthcoming changes to the online format for Cell articles in which we intend to move the supplemental figures and text into the presentation of the main article as a clearly delineated second or nested layer. In this new online format, readers will be able to opt for either a basic or an extended view. In the basic view they can easily follow the flow of the main findings as in the current print version, which hopefully encourages crossdisciplinary browsing, whereas in the extended view they can see all the supplemental text and figures positioned adjacent to the sections of the main article to which they relate. In this way, over time the concept of supplemental material will gradually give way to a more modern concept of a hierarchical or layered presentation in which a reader can define which level of detail best fits their interests and needs. We are implementing the new guidelines for papers to be published in Cell starting in January 2010 and in the other Cell Press journals shortly afterwards. Authors and reviewers will begin to notice the changes already this fall. As with all new initiatives at Cell, we welcome feedback from the community as we continue to evolve the presentation of scientific articles to meet the changing needs of the scientific community.

The serine threonine protein kinase encoded by the shaggy locus has been implicated in neurogenesis in Drosophila. In vertebrates, the shaggy homolog, GSK3beta, is involved in early pattern formation, specifically in setting up the dorsal ventral axis. In the present study we have cloned the Xenopus homolog of the shaggy kinase and show (1) that GSK3beta is expressed in the right time and place to play a role in primary neurogenesis in Xenopus; (2) that overexpression of wild-type GSK3beta leads to a decrease in the number of primary neurons; (3) that inhibition of endogenous GSK3beta activity with overexpression of a dominant negative GSK3beta construct leads to an increase in the number of primary neurons; and (4) that GSK3beta inhibits the ability of neurogenin and NeuroD to produce ectopic tubulin expression, but does not inhibit the ability of neurogenin to produce ectopic NeuroD. On the basis of these data we propose that GSK3beta inhibits the function of NeuroD and therefore prevents neuronal differentiation at a relatively late stage in the developmental pathway.

We have examined cells cultured from ectoderm-misexpressing Neurogenin1 (Ngn1) to describe better the extent to which this gene can control aspects of neuronal phenotype including motility, morphology, excitability, and synaptic properties. Like primary spinal neurons which normally express Ngn1, cells in Ngn1-misexpressing cultures exhibit a motility-correlated behavior called circus movements prior to neuritogenesis. Misexpression of NeuroD also causes circus movements and later neuronal differentiation. GSK3β, which inhibits NeuroD functionin vivo,blocks both Ngn1-induced and NeuroD-induced neuronal differentiation, while Notch signaling inhibits only Ngn1-induced neuronal differentiation, confirming that NeuroD is downstream of Ngn1 and insensitive to Notch inhibition. While interfering with NeuroD function in ventral ectoderm inhibits both circus movements and neuronal differentiation, such inhibition in the neural plate inhibits only neuronal differentiation, suggesting that additional factors regulate circus movements in the neural ectoderm. Ngn1-misexpressing cells extend N-tubulin-positive neurites and exhibit tetrodotoxin-sensitive action potentials. Unlike the majority of cultured spinal neurons, however, Ngn1-misexpressing cells do not respond to glutamate and do not form functional synapses with myocytes, suggesting that these cells are either like Rohon-Beard sensory neurons or are not fully differentiated.