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Extracellular matrices in vivo are heterogeneous structures containing gaps that cells bridge with an actomyosin network. To understand the basis of bridging, we plated cells on surfaces patterned with fibronectin (FN)-coated stripes separated by non-adhesive regions. Bridges developed large tensions where concave cell edges were anchored to FN by adhesion(More)
Egg-laying hormone (ELH), a neuropeptide synthesized by the bag cell neurons, induces egg laying and its correlated behavior in Aplysia californica. In the present study, ELH has been purified to homogeneity and its primary structure has been determined. We find this molecule to have 36 amino acid residues with a M(r) of 4385 and a calculated isoelectric(More)
While gastrulation movements offer mechanistic paradigms for how collective cellular movements shape developing embryos, far less is known about coordinated cellular movements that occur later in development. Studying eyelid closure, we explore a case where an epithelium locally reshapes, expands, and moves over another epithelium. Live imaging, gene(More)
Tissue growth is the multifaceted outcome of a cell's intrinsic capabilities and its interactions with the surrounding environment. Decoding these complexities is essential for understanding human development and tumorigenesis. Here we tackle this problem by carrying out the first genome-wide RNA-interference-mediated screens in mice. Focusing on skin(More)
Planar cell polarity (PCP) is the collective polarization of cells along the epithelial plane, a process best understood in the terminally differentiated Drosophila wing. Proliferative tissues such as mammalian skin also display PCP, but the mechanisms that preserve tissue polarity during proliferation are not understood. During mitosis,(More)
Adult stem cells sustain tissue maintenance and regeneration throughout the lifetime of an animal. These cells often reside in specific signalling niches that orchestrate the stem cell's balancing act between quiescence and cell-cycle re-entry based on the demand for tissue regeneration. How stem cells maintain their capacity to replenish themselves after(More)
Mining modern genomics for cancer therapies is predicated on weeding out "bystander" alterations (nonconsequential mutations) and identifying "driver" mutations responsible for tumorigenesis and/or metastasis. We used a direct in vivo RNA interference (RNAi) strategy to screen for genes that upon repression predispose mice to squamous cell carcinomas(More)
Hair production is fueled by stem cells (SCs), which transition between cyclical bouts of rest and activity. Here, we explore why hair growth wanes with age. We show that aged hair follicle SCs (HFSCs) in mice exhibit enhanced resting and abbreviated growth phases and are delayed in response to tissue-regenerating cues. Aged HFSCs are poor at initiating(More)
Two neuroactive peptides, A and B, have been isolated from the atrial gland in the reproductive tract of Aplysia. Each of the two peptides is able to induce egg-laying behavior in recipient animals. In vitro recordings from the abdominal ganglion show that both peptides also trigger longlasting discharges in the bag cell neurons at concentrations around 0.1(More)