Combined quantification of intracellular (phospho-)proteins and transcriptomics from fixed single cells, bioRxiv, 2018-06-27
AbstractEnvironmental stimuli often lead to heterogeneous cellular responses and transcriptional output. We developed single-cell RNA and Immunodetection (RAID) to allow combined analysis the transcriptome and intracellular (phospho-)proteins from fixed single cells. RAID successfully recapitulated differentiation-state changes at the protein and mRNA level in human keratinocytes. Furthermore, we show that differentiated keratinocytes that retain high phosphorylated FAK levels, a feature associated with stem cells, also express a selection of stem cell associated transcripts. Our data demonstrates that RAID allows investigation of heterogenenous cellular responses to environmental signals at the mRNA and phospho-proteome level.
biorxiv genomics 100-200-users 2018Up, down, and out optimized libraries for CRISPRa, CRISPRi, and CRISPR-knockout genetic screens, bioRxiv, 2018-06-27
ABSTRACTAdvances in CRISPR-Cas9 technology have enabled the flexible modulation of gene expression at large scale. In particular, the creation of genome-wide libraries for CRISPR knockout (CRISPRko), CRISPR interference (CRISPRi), and CRISPR activation (CRISPRa) has allowed gene function to be systematically interrogated. Here, we evaluate numerous CRISPRko libraries and show that our recently-described CRISPRko library (Brunello) is more effective than previously published libraries at distinguishing essential and non-essential genes, providing approximately the same perturbation-level performance improvement over GeCKO libraries as GeCKO provided over RNAi. Additionally, we developed genome-wide libraries for CRISPRi (Dolcetto) and CRISPRa (Calabrese). Negative selection screens showed that Dolcetto substantially outperforms existing CRISPRi libraries with fewer sgRNAs per gene and achieves comparable performance to CRISPRko in the detection of gold-standard essential genes. We also conducted positive selection CRISPRa screens and show that Calabrese outperforms the SAM library approach at detecting vemurafenib resistance genes. We further compare CRISPRa to genome-scale libraries of open reading frames (ORFs). Together, these libraries represent a suite of genome-wide tools to efficiently interrogate gene function with multiple modalities.tracr
biorxiv genomics 0-100-users 2018Career Choice, Gender, and Mentor Impact Results of the U.S. National Postdoc Survey, bioRxiv, 2018-06-26
AbstractThe postdoctoral community is an essential component of the academic and scientific workforce. As economic and political pressures impacting these enterprises continue to change, the postdoc experience has evolved from short, focused periods of training into often multidisciplinary, extended positions with less clear outcomes. As efforts are underway to amend U.S. federally funded research policies, the paucity of postdoc data has made evaluating the impact of policy recommendations challenging. Here we present comprehensive survey results from over 7,600 postdocs based at 351 academic and non-academic U.S. institutions in 2016. In addition to demographic and salary information, we present multivariate analyses on the factors that influence postdoc career plans and mentorship satisfaction in this population. We further analyze gender dynamics and expose wage disparities and career choice differences. Academic research positions remain the predominant career choice of postdocs in the U.S., although unequally between postdocs based on gender and residency status. Receiving mentorship training during the postdoctoral period has a large, positive effect on postdoc mentorship satisfaction. Strikingly, the quality of and satisfaction with postdoc mentorship appears to also heavily influence career choice. The data presented here are the most comprehensive data on the U.S. postdoc population to date. These results provide an evidence basis for informing government and institutional policies, and establish a critical cornerstone for quantifying the effects of future legislation aimed at the academic and scientific workforce.
biorxiv scientific-communication-and-education 200-500-users 2018Reduced signal for polygenic adaptation of height in UK Biobank, bioRxiv, 2018-06-25
AbstractSeveral recent papers have reported strong signals of selection on European polygenic height scores. These analyses used height effect estimates from the GIANT consortium and replication studies. Here, we describe a new analysis based on the the UK Biobank (UKB), a large, independent dataset. We find that the signals of selection using UKB effect-size estimates for height are strongly attenuated or absent. We also provide evidence that previous analyses were confounded by population stratification Therefore, the conclusion of strong polygenic adaptation now lacks support. Moreover, these discrepancies highlight (1) that methods for correcting for population stratification in GWAS may not always be sufficient for polygenic trait analyses, and (2) that claims of differences in polygenic scores between populations should be treated with caution until these issues are better understood.
biorxiv evolutionary-biology 200-500-users 2018Analysis and Correction of Inappropriate Image Duplication The Molecular and Cellular Biology Experience, bioRxiv, 2018-06-24
AbstractThe present study analyzed 960 papers published in Molecular and Cellular Biology (MCB) from 2009-2016 and found 59 (6.1%) to contain inappropriately duplicated images. The 59 instances of inappropriate image duplication led to 42 corrections, 5 retractions and 12 instances in which no action was taken. Our experience suggests that the majority of inappropriate image duplications result from errors during figure preparation that can be remedied by correction. Nevertheless, ~10% of papers with inappropriate image duplications in MCB were retracted. If this proportion is representative, then as many as 35,000 papers in the literature are candidates for retraction due to image duplication. The resolution of inappropriate image duplication concerns after publication required an average of 6 h of journal staff time per published paper. MCB instituted a pilot program to screen images of accepted papers prior to publication that identified 12 manuscripts (14.5% out of 83) with image concerns in two months. The screening and correction of papers before publication required an average of 30 min of staff time per problematic paper. Image screening can identify papers with problematic images prior to publication, reduces post-publication problems and requires significantly less staff time than the correction of problems after publication.
biorxiv scientific-communication-and-education 100-200-users 2018Spatial Organization of Rho GTPase signaling by RhoGEFRhoGAP proteins, bioRxiv, 2018-06-24
AbstractRho GTPases control cell morphogenesis and thus fundamental processes in all eukaryotes. They are regulated by 145 RhoGEF and RhoGAP multi-domain proteins in humans. How the Rho signaling system is organized to generate localized responses in cells and prevent their spreading is not understood. Here, we systematically characterized the substrate specificities, localization and interactome of the RhoGEFsRhoGAPs and revealed their critical role in contextualizing and spatially delimiting Rho signaling. They localize to multiple compartments providing positional information, are extensively interconnected to jointly coordinate their signaling networks and are widely autoinhibited to remain sensitive to local activation. RhoGAPs exhibit lower substrate specificity than RhoGEFs and may contribute to preserving Rho activity gradients. Our approach led us to uncover a multi-RhoGEF complex downstream of G-protein-coupled receptors controlling a Cdc42RhoA crosstalk. The spatial organization of Rho signaling thus differs from other small GTPases and expands the repertoire of mechanisms governing localized signaling activity.
biorxiv cell-biology 100-200-users 2018