SummaryRecently, a new regulatory circuitry has been identified in which RNAs can crosstalk with each other by competing for shared microRNAs. Such competing endogenous RNAs (ceRNAs) regulate the distribution of miRNA molecules on their targets and thereby impose an additional level of post-transcriptional regulation. Here we identify a muscle-specific long noncoding RNA, linc-MD1, which governs the time of muscle differentiation by acting as a ceRNA in mouse and human myoblasts. Downregulation or overexpression of linc-MD1 correlate with retardation or anticipation of the muscle differentiation program, respectively. We show that linc-MD1 “sponges” miR-133 and miR-135 to regulate the expression of MAML1 and MEF2C, transcription factors that activate muscle-specific gene expression. Finally, we demonstrate that linc-MD1 exerts the same control over differentiation timing in human myoblasts, and that its levels are strongly reduced in Duchenne muscle cells. We conclude that the ceRNA network plays an important role in muscle differentiation.

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Single-cell profiling methods have had a profound impact on the understanding of cellular heterogeneity. While genomes and transcriptomes can be explored at the single-cell level, single-cell profiling of proteomes is not yet established. Here we describe new single-molecule protein sequencing and identification technologies alongside innovations in mass spectrometry that will eventually enable broad sequence coverage in single-cell profiling. These technologies will in turn facilitate biological discovery and open new avenues for ultrasensitive disease diagnostics.

In this work, we study the wetting of a surface decorated with one nanogroove by a bulk Lennard-Jones liquid at various temperatures and densities. We used atomistic simulations aimed at computing the free energy of the stable and metastable states of the system, as well as the intermediate states separating them. We found that the usual description in terms of Cassie-Baxter and Wenzel states is insufficient, as the system presents two states of the Cassie-Baxter type. These states are characterized by different curvatures of the meniscus. The measured free energy barrier separating the Cassie-Baxter from the Wenzel state (and vice versa) largely exceeds the thermal energy, attesting the existence of Cassie-Baxter/Wenzel metastabilities. Finally, we found that the Cassie-Baxter/Wenzel transition follows an asymmetric path, with the formation of a liquid finger on one side of the groove and a vapor bubble on the opposite side.

In this Letter, we develop a continuum theory for the Cassie-Baxter-Wenzel (CB-W) transition. The proposed model accounts for the metastabilities in the wetting of rough hydrophobic surfaces, allows us to reconstruct the transition mechanism, and identifies the free energy barriers separating the CB and W states as a function of the liquid pressure. This information is crucial in the context of superhydrophobic surfaces, where there is interest in extending the duration of the metastable superhydrophobic CB state. The model is validated against free energy atomistic simulations.