De novo assembly of a transcriptome for the cricket Gryllus bimaculatus prothoracic ganglion: An invertebrate model for investigating adult central nervous system compensatory plasticity.

The auditory system of the cricket, Gryllus bimaculatus, demonstrates an unusual amount of anatomical plasticity in response to injury, even in adults. Unilateral removal of the ear causes deafferented auditory neurons in the prothoracic ganglion to sprout dendrites across the midline, a boundary they typically respect, and become synaptically connected to the auditory afferents of the contralateral ear. The molecular basis of this sprouting and novel synaptogenesis in the adult is not understood.

Cell cycle features of C. elegans germline stem/progenitor cells vary temporally and spatially.

Many organisms accumulate a pool of germline stem cells during development that is maintained in later life. The dynamics of establishment, expansion and homeostatic maintenance of this pool are subject to both developmental and physiological influences including the availability of a suitable niche microenvironment, nutritional status, and age. Here, we investigated the dynamics of germline proliferation during stages of expansion and homeostasis, using the C.

Targeting Homologous Recombination in Notch-Driven C. elegans Stem Cell and Human Tumors.

Mammalian NOTCH1-4 receptors are all associated with human malignancy, although exact roles remain enigmatic. Here we employ glp-1(ar202), a temperature-sensitive gain-of-function C. elegans NOTCH mutant, to delineate NOTCH-driven tumor responses to radiotherapy.

Irises: A practical tool for image-based analysis of cellular DNA content.

The DNA content of nuclei is a valuable measure of cell cycle status. Irises is a software tool to facilitate systematic in situ determination of DNA content for cell cycle analysis at single-nucleus resolution within complex tissues. We demonstrate the utility of the tool with analysis of DNA content in germline nuclei of C.

Sensory regulation of the C. elegans germline through TGF-β-dependent signaling in the niche.

The proliferation/differentiation balance of stem and progenitor cell populations must respond to the physiological needs of the organism [1, 2]. Mechanisms underlying this plasticity are not well understood. The C.

Insulin signaling promotes germline proliferation in C. elegans.

Cell proliferation must be coordinated with cell fate specification during development, yet interactions among pathways that control these two critical aspects of development are not well understood. The coordination of cell fate specification and proliferation is particularly crucial during early germline development, when it impacts the establishment of stem/progenitor cell populations and ultimately the production of gametes. In C.

Rac1 accumulates in the nucleus during the G2 phase of the cell cycle and promotes cell division.

Rac1 regulates a wide variety of cellular processes. The polybasic region of the Rac1 C terminus functions both as a plasma membrane-targeting motif and a nuclear localization sequence (NLS). We show that a triproline N-terminal to the polybasic region contributes to the NLS, which is cryptic in the sense that it is strongly inhibited by geranylgeranylation of the adjacent cysteine.

The use of GFP to localize Rho GTPases in living cells.

The green fluorescent protein (GFP) of the jellyfish Aequorea victoria has revolutionized the study of protein localization and dynamics. GFP fusions permit analysis of proteins in living cells and offer distinct advantages over conventional immunofluorescence. Among these are lower background, higher resolution, robust dual color colocalization, and avoidance of fixation artifacts.

Roles of the Rac1 and Rac3 GTPases in human tumor cell invasion.

Members of the Rho family of small GTPases have been shown to be involved in tumorigenesis and metastasis. Currently, most of the available information on the function of Rho proteins in malignant transformation is based on the use of dominant-negative mutants of these GTPases. The specificity of these dominant-negative mutants is limited however.

Postprenylation CAAX processing is required for proper localization of Ras but not Rho GTPases.

The CAAX motif at the C terminus of most monomeric GTPases is required for membrane targeting because it signals for a series of three posttranslational modifications that include isoprenylation, endoproteolytic release of the C-terminal- AAX amino acids, and carboxyl methylation of the newly exposed isoprenylcysteine. The individual contributions of these modifications to protein trafficking and function are unknown. To address this issue, we performed a series of experiments with mouse embryonic fibroblasts (MEFs) lacking Rce1 (responsible for removal of the -AAX sequence) or Icmt (responsible for carboxyl methylation of the isoprenylcysteine).

Membrane trafficking of heterotrimeric G proteins via the endoplasmic reticulum and Golgi.

Membrane targeting of G-protein alphabetagamma heterotrimers was investigated in live cells by use of Galpha and Ggamma subunits tagged with spectral mutants of green fluorescent protein. Unlike Ras proteins, Gbetagamma contains a single targeting signal, the CAAX motif, which directed the dimer to the endoplasmic reticulum. Endomembrane localization of farnesylated Ggamma(1), but not geranylgeranylated Ggamma(2), required carboxyl methylation.