Publisher Correction: FGF signalling controls the specification of hair placode-derived SOX9 positive progenitors to Merkel cells.

The originally published version of this Article contained an error in Figure 2. In panel e, the blue bar was incorrectly labelled 'KRT8(+)/TOMATO(-)'. Furthermore, during the process of preparing a correction, the publication date of the Article was inadvertently changed to June 20th 2018. Both of these errors have been corrected in the PDF and HTML versions of the Article

FGF signalling controls the specification of hair placode-derived SOX9 positive progenitors to Merkel cells

Merkel cells are innervated mechanosensory cells responsible for light-touch sensations. In murine dorsal skin, Merkel cells are located in touch domes and found in the epidermis around primary hairs. While it has been shown that Merkel cells are skin epithelial cells, the progenitor cell population that gives rise to these cells is unknown. Here, we show that during embryogenesis, SOX9-positive (+) cells inside hair follicles, which were previously known to give rise to hair follicle stem cells (HFSCs) and cells of the hair follicle lineage, can also give rise to Merkel Cells. Interestingly, while SOX9 is critical for HFSC specification, it is dispensable for Merkel cell formation. Conversely, FGFR2 is required for Merkel cell formation but is dispensable for HFSCs. Together, our studies uncover SOX9(+) cells as precursors of Merkel cells and show the requirement for FGFR2-mediated epithelial signalling in Merkel cell specification.Peer reviewe

Identification of chemosensory receptor genes in Manduca sexta and knockdown by RNA interference

Insects detect environmental chemicals via a large and rapidly evolving family of chemosensory receptor proteins. Although our understanding of the molecular genetic basis for Drosophila chemoreception has increased enormously in the last decade, similar understanding in other insects remains limited. The tobacco hornworm, Manduca sexta, has long been an important model for insect chemosensation, particularly from ecological, behavioral, and physiological standpoints. It is also a major agricultural pest on solanaceous crops. However, little sequence information and lack of genetic tools has prevented molecular genetic analysis in this species. The ability to connect molecular genetic mechanisms, including potential lineage-specific changes in chemosensory genes, to ecologically relevant behaviors and specializations in M. sexta would be greatly beneficial. Here, we sequenced transcriptomes from adult and larval chemosensory tissues and identified chemosensory genes based on sequence homology. We also used dsRNA feeding as a method to induce RNA interference in larval chemosensory tissues. We report identification of new chemosensory receptor genes including 17 novel odorant receptors and one novel gustatory receptor. Further, we demonstrate that systemic RNA interference can be used in larval olfactory neurons to reduce expression of chemosensory receptor transcripts. Together, our results further the development of M. sexta as a model for functional analysis of insect chemosensation

Rare and low-frequency coding variants alter human adult height

Height is a highly heritable, classic polygenic trait with ~700 common associated variants identified so far through genome - wide association studies . Here , we report 83 height - associated coding variants with lower minor allele frequenc ies ( range of 0.1 - 4.8% ) and effects of up to 2 16 cm /allele ( e.g. in IHH , STC2 , AR and CRISPLD2 ) , >10 times the average effect of common variants . In functional follow - up studies, rare height - increasing alleles of STC2 (+1 - 2 cm/allele) compromise d proteolytic inhibition of PAPP - A and increased cleavage of IGFBP - 4 in vitro , resulting in higher bioavailability of insulin - like growth factors . The se 83 height - associated variants overlap genes mutated in monogenic growth disorders and highlight new biological candidates ( e.g. ADAMTS3, IL11RA, NOX4 ) and pathways ( e.g . proteoglycan/ glycosaminoglycan synthesis ) involved in growth . Our results demonstrate that sufficiently large sample sizes can uncover rare and low - frequency variants of moderate to large effect associated with polygenic human phenotypes , and that these variants implicate relevant genes and pathways

Development of a Web-Based Decision Aid and Planning Tool for Family Building After Cancer (Roadmap to Parenthood): Usability Testing

BackgroundOwing to gonadotoxic cancer treatments, young adult female survivors often report uncertainty about their fertility, reproductive potential, and family-building options after treatment. Roadmap to Parenthood is a web-based decision aid and planning tool for family building after cancer. ObjectiveAs part of a patient-centered development process, this study evaluated the usability of the decision aid website to inform design modifications and improve user experience. MethodsIn total, 2 rounds of usability testing were conducted with the target population of young adult female cancer survivors. During the testing sessions, participants viewed the website twice; first, as a think-aloud exercise, and second, while a researcher interrupted at key points to obtain user feedback. Quantitative and qualitative data were collected to assess website usability. Quantitative measures included the System Usability Scale, WebQual, and eHealth Impact Questionnaire. An exit interview with open-ended questions gathered feedback on likes and dislikes and suggestions for improvement. ResultsParticipants (N=10) were young adult women, with average age of 30.9 (SD 4.51) years, and average time since treatment was 4.44 (SD 3.56) years. Website usability scores improved on the System Usability Scale from “acceptable” in round 1 to “excellent” in round 2 after making design changes based on user feedback (scores of 68 and 89.4, respectively). WebQual scores showed similar improvement from round 1 to round 2 of testing (mean 5.6 to 6.25; range 1-7). On the eHealth Impact Questionnaire, the information and presentation of the website was perceived as comprehensive, easy to understand, and trustworthy. Participants also reported improved confidence to discuss and manage fertility and family-building issues and felt encouraged to play a more active role in managing their fertility. In all, 3 usability themes were identified from the qualitative feedback: ease of use, visibility and navigation, and informational content and usefulness. Overall feedback was positive, and participants reported intentions to use the decision aid website in the future. In total, 10% (1/10) of the participants reported negative emotions when learning about infertility risks and potential family-building challenges. ConclusionsWebsite usability improved after design changes were made in response to user feedback. Young adult female survivors reported positive views about the website and indicated that the decision aid would be useful in decision-making about family building after cancer. Future studies will include further design modifications to consider the emotional experiences of users and any additional navigational features or content to optimize the ease of use and support provided by the tool

Polycomb-Mediated Repression and Sonic Hedgehog Signaling Interact to Regulate Merkel Cell Specification during Skin Development

An increasing amount of evidence indicates that developmental programs are tightly regulated by the complex interplay between signaling pathways, as well as transcriptional and epigenetic processes. Here, we have uncovered coordination between transcriptional and morphogen cues to specify Merkel cells, poorly understood skin cells that mediate light touch sensations. In murine dorsal skin, Merkel cells are part of touch domes, which are skin structures consisting of specialized keratinocytes, Merkel cells, and afferent neurons, and are located exclusively around primary hair follicles. We show that the developing primary hair follicle functions as a niche required for Merkel cell specification. We find that intraepidermal Sonic hedgehog (Shh) signaling, initiated by the production of Shh ligand in the developing hair follicles, is required for Merkel cell specification. The importance of Shh for Merkel cell formation is further reinforced by the fact that Shh overexpression in embryonic epidermal progenitors leads to ectopic Merkel cells. Interestingly, Shh signaling is common to primary, secondary, and tertiary hair follicles, raising the possibility that there are restrictive mechanisms that regulate Merkel cell specification exclusively around primary hair follicles. Indeed, we find that loss of Polycomb repressive complex 2 (PRC2) in the epidermis results in the formation of ectopic Merkel cells that are associated with all hair types. We show that PRC2 loss expands the field of epidermal cells competent to differentiate into Merkel cells through the upregulation of key Merkel-differentiation genes, which are known PRC2 targets. Importantly, PRC2-mediated repression of the Merkel cell differentiation program requires inductive Shh signaling to form mature Merkel cells. Our study exemplifies how the interplay between epigenetic and morphogen cues regulates the complex patterning and formation of the mammalian skin structures

Cerebellar nuclei excitatory neurons regulate developmental scaling of presynaptic Purkinje cell number and organ growth.

For neural systems to function effectively, the numbers of each cell type must be proportioned properly during development. We found that conditional knockout of the mouse homeobox genes En1 and En2 in the excitatory cerebellar nuclei neurons (eCN) leads to reduced postnatal growth of the cerebellar cortex. A subset of medial and intermediate eCN are lost in the mutants, with an associated cell non-autonomous loss of their presynaptic partner Purkinje cells by birth leading to proportional scaling down of neuron production in the postnatal cerebellar cortex. Genetic killing of embryonic eCN throughout the cerebellum also leads to loss of Purkinje cells and reduced postnatal growth but throughout the cerebellar cortex. Thus, the eCN play a key role in scaling the size of the cerebellum by influencing the survival of their Purkinje cell partners, which in turn regulate production of granule cells and interneurons via the amount of sonic hedgehog secreted

Publisher Correction: FGF signalling controls the specification of hair placode-derived SOX9 positive progenitors to Merkel cells.

The originally published version of this Article contained an error in Figure 2. In panel e, the blue bar was incorrectly labelled 'KRT8(+)/TOMATO(-)'. Furthermore, during the process of preparing a correction, the publication date of the Article was inadvertently changed to June 20th 2018. Both of these errors have been corrected in the PDF and HTML versions of the Article

Shh overexpression results in increased formation of cells expressing Merkel markers.

<p>(A) Schematic diagram showing transgenic mouse and lentiviral constructs for the Shh overexpression experiment. CD1 female mice were mated with male Rosa26-rtTA mice and <i>in utero</i> lentiviral injections were performed in pregnant females E9. Doxycycline treatment was initiated by gavage at E12, and females were continuously fed Doxycycline until embryo collection at E17. In the presence of Doxycycline, lentivirus-injected mouse embryos express both H2B-RFP and Shh proteins. (B-E) IF stainings showing the altered morphology of epidermis infected with Shh+H2B-RFP (C,C’) and the significant increase in the numbers of Krt8(+) (K8) cells in the infected epidermis (C,C’,E) compared to control, un-infected epidermis (E17 control) (B,B’,D). Quantification of Krt8(+) cells per mm of back skin in E17 control and Shh overexpression (right panel) (p<0.0001). (F,F’) IF staining for Phospho-Histone H3 (PH3) showing a significant increase in proliferation in E17 Shh o/exp epidermis (F’) compared to control (F). Quantification of number of PH3(+) per mm² of Krt14(+) epidermal cells is represented on the right (p<0.0001). (G,G’) TUNEL staining showing no increase in apoptosis in E17 Shh o/exp epidermis (G’) compared to control (G). Note that cells undergoing cornification are TUNEL(+), as previously reported [<a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1006151#pgen.1006151.ref033" target="_blank">33</a>]. (H-I’) IF staining showing an increase in the number of Sox2(+)/Krt8(+) cells in E17 Shh o/exp epidermis (I,I’) compared to control (H,H’). (J-K’) IF stainings showing an increase in the number of Isl1(+)/Krt8(+) cells in E17 Shh o/exp epidermis (K,K’) compared to control (J,J’). Scale bars: (B-C’): 100μm; (D-K’): 25 μm.</p