[
Biomolecules,
2020]
Since its discovery in <i>Drosophila</i>, the Notch signaling pathway has been studied in numerous developmental contexts in diverse multicellular organisms. The role of Notch signaling in nervous system development has been extensively investigated by numerous scientists, partially because many of the core Notch signaling components were initially identified through their dramatic 'neurogenic' phenotype of developing fruit fly embryos. Components of the Notch signaling pathway continue to be expressed in mature neurons and glia cells, which is suggestive of a role in the post-developmental nervous system. The Notch pathway has been, so far, implicated in learning and memory, social behavior, addiction, and other complex behaviors using genetic model organisms including <i>Drosophila</i> and mice. Additionally, Notch signaling has been shown to play a modulatory role in several neurodegenerative disease model animals and in mediating neural toxicity of several environmental factors. In this paper, we summarize the knowledge pertaining to the post-developmental roles of Notch signaling in the nervous system with a focus on discoveries made using the fruit fly as a model system as well as relevant studies in <i>C elegans</i>, mouse, rat, and cellular models. Since components of this pathway have been implicated in the pathogenesis of numerous psychiatric and neurodegenerative disorders in human, understanding the role of Notch signaling in the mature brain using model organisms will likely provide novel insights into the mechanisms underlying these diseases.
[
Journal of Gerontology,
1998]
Vanfleteren and colleagues present an interesting example of environmental conditions altering the kinetics of survival. Most previous studies of survival in C. elegans have used abundant bacteria as a food source. Such studies have found that the Gompertz function (exponential growth in mortality rate with age) gives a relatively good fit to survival curves, but that there is some deceleration in the rate of growth of mortality later in the life span. Yulong Yang and I have completed dozens of studies of small populations of the wild-type strain, N2, as well as strains TJ401, TJ411, TJ412,and BA713 in the presence of abundant bacteria in liquid or on agar. Survival curves were better fit by Gompertz more often than by Weibull or logistic functions (unpublished observations).
[
RNA Biol,
2014]
Small RNA programmed Argonautes are sophisticated cellular effector platforms known to be involved in a diverse array of functions ranging from mRNA cleavage, translational inhibition, DNA elimination, epigenetic silencing, alternative splicing and even gene activation. First observed in human cells, small RNA-induced gene activation, also known as RNAa, involves the targeted recruitment of Argonaute proteins to specific promoter sequences followed by induction of stable epigenetic changes which promote transcription. The existence of RNAa remains contentious due to its elusive mechanism. A string of recent studies in C. elegans provides unequivocal evidence for RNAa's fundamental role in sculpting the epigenetic landscape and maintaining active transcription of endogenous genes and supports the presence of a functionally sophisticated network of small RNA-Argonaute pathways consisting of opposite yet complementary "yin and yang" regulatory elements. In this review, we summarize key findings from recent studies of endogenous RNAa in C. elegans, with an emphasis on the Argonaute protein CSR-1.