ePRINT: exonuclease assisted mapping of protein-RNA interactions.

RNA-binding proteins (RBPs) regulate key aspects of RNA processing including alternative splicing, mRNA degradation and localization by physically binding RNA molecules. Current methods to map these interactions, such as CLIP, rely on purifying single proteins at a time. Our new method, ePRINT, maps RBP-RNA interaction networks on a global scale without purifying individual RBPs. ePRINT uses exoribonuclease XRN1 to precisely map the 5' end of the RBP binding site and uncovers direct and indirect targets of an RBP of interest. Importantly, ePRINT can also uncover RBPs that are differentially activated between cell fate transitions, including neural progenitor differentiation into neurons.

Sexual Behaviors, Satisfaction, and Intentions to Engage in Casual Sexual Relationships and Experiences in Emerging Adulthood.

The present study examined the role of sexual behavior and sexual satisfaction in casual sexual relationships and experiences (CSREs) on both immediate and long-term intentions to engage in further CSREs in a sample of emerging adults. We examined how four different operationalizations of sexual behavior (1) Penetrative sexual behaviors not including oral sex vs. non-penetrative sexual behaviors, (2) Penetrative sexual behaviors including oral sex vs. non-penetrative sexual behaviors, (3) Most sexually intimate behaviors, and (4) A sum score of sexual behaviors) and sexual satisfaction were associated with immediate intentions to engage in CSREs (measured during a five-day daily diary) and long-term intentions to engage in CSREs (measured one month later). Follow-up analyses examined intentions to engage in additional CSREs with a different partner. Our sample (N = 274) included both college-attending and non-college-attending emerging adults. Path analysis models indicated that more sexually intimate behaviors were associated with higher sexual satisfaction following a CSRE. Additionally, sexual satisfaction, but not type of sexual behavior, was associated with both immediate and long-term intentions to engage in CSREs above and beyond the effects of sample, gender, alcohol consumption, and previous CSREs. Follow-up analyses indicated that only alcohol consumption and gender were significantly associated with immediate intentions to engage in a CSRE, and only daily diary intentions and gender were significantly associated with long-term intentions to engage in a CSRE. Overall, these findings support previous research that suggests positive outcomes of a CSRE (sexual satisfaction) are associated with higher intentions to engage in future CSREs.

Upregulation of ß-catenin due to loss of miR-139 contributes to motor neuron death in amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the loss of motor neurons (MNs). There are no effective treatments and patients usually die within 2-5 years of diagnosis. Emerging commonalities between familial and sporadic cases of this complex multifactorial disorder include disruption to RNA processing and cytoplasmic inclusion bodies containing TDP-43 and/or FUS protein aggregates. Both TDP-43 and FUS have been implicated in RNA processing functions, including microRNA biogenesis, transcription, and splicing. In this study, we explore the misexpression of microRNAs in an iPSC-based disease model of FUS ALS. We identify the downregulation of miR-139, an MN-enriched microRNA, in FUS and sporadic ALS MN. We discover that miR-139 downregulation leads to the activation of canonical WNT signaling and demonstrate that the WNT transcriptional mediator ß-catenin is a major driver of MN degeneration in ALS. Our results highlight the importance of homeostatic RNA networks in ALS.

Single-cell transcriptomics identifies master regulators of neurodegeneration in SOD1 ALS iPSC-derived motor neurons.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative condition characterized by the loss of motor neurons. We utilized single-cell transcriptomics to uncover dysfunctional pathways in degenerating motor neurons differentiated from SOD1 E100G ALS patient-derived induced pluripotent stem cells (iPSCs) and respective isogenic controls. Differential gene expression and network analysis identified activation of developmental pathways and core transcriptional factors driving the ALS motor neuron gene dysregulation. Specifically, we identified activation of SMAD2, a downstream mediator of the transforming growth factor ß (TGF-ß) signaling pathway as a key driver of SOD1 iPSC-derived motor neuron degeneration. Importantly, our analysis indicates that activation of TGFß signaling may be a common mechanism shared between SOD1, FUS, C9ORF72, VCP, and sporadic ALS motor neurons. Our results demonstrate the utility of single-cell transcriptomics in mapping disease-relevant gene regulatory networks driving neurodegeneration in ALS motor neurons. We find that ALS-associated mutant SOD1 targets transcriptional networks that perturb motor neuron homeostasis.