Plant microRNAs slow virus-driven aging
The evolutionarily conserved nutrient-sensing signaling pathways that accelerate chronological aging in yeast (Figure 9) are known to stimulate chronological senescence and geroconversion of post-mitotic human cells; these pathways are likely to expedite organismal aging and cancer development in humans [87-93].
There is no experimental evidence of biologically-based cause and effect that starts with the conservation of nutrient-sensing pathways. The nutrient-sensing pathways link the de novo creation of G protein-coupled receptors to the energy-dependent physiology of reproduction in all living genera via ecological variation and energy-dependent ecological adaptation. Ecological variation and energy-dependent ecological adaptation link the epigenetic landscape to the physical landscape of supercoiled DNA, which protects all organized genomes from virus-driven entropy.
Yeast was utilized as a model organism, one that has been extensively used for several reasons, such as: yeast is cheap and easy to grow, it has a small genome that has many similarities to human genes, it has a short and simple life cycle, and they can proliferate in both the haploid and diploid states. Importantly, yeast also ages in a way that is like that of humans. In both organisms, cascades of chemical reactions or signaling pathways control the process.
Yet another kind of epigenetic imprinting occurs in species as diverse as yeast, Drosophila, mice, and humans and is based upon small DNA-binding proteins called “chromo domain” proteins, e.g., polycomb. These proteins affect chromatin structure, often in telomeric regions, and thereby affect transcription and silencing of various genes (Saunders, Chue, Goebl, Craig, Clark, Powers, Eissenberg, Elgin, Rothfield, and Earnshaw, 1993; Singh, Miller, Pearce, Kothary, Burton, Paro, James, and Gaunt, 1991; Trofatter, Long, Murrell, Stotler, Gusella, and Buckler, 1995). Small intranuclear proteins also participate in generating alternative splicing techniques of pre-mRNA and, by this mechanism, contribute to sexual differentiation in at least two species, Drosophila melanogaster and Caenorhabditis elegans (Adler and Hajduk, 1994; de Bono, Zarkower, and Hodgkin, 1995; Ge, Zuo, and Manley, 1991; Green, 1991; Parkhurst and Meneely, 1994; Wilkins, 1995; Wolfner, 1988). That similar proteins perform functions in humans suggests the possibility that some human sex differences may arise from alternative splicings of otherwise identical genes.
Term-seq reveals abundant ribo-regulation of antibiotics resistance in bacteria was reported as: Wanted: Transcriptional Regulators and as Search for Switches in the printed version of The Scientist (August, 2016) with the subheading:
An unbiased screen identifies bacterial riboswitches-built-in self regulators of mRNA transcription.
Nature has evolved a staggering array of mechanisms for regulating gene expression, but few are so simple and elegant as the riboswitch. These RNA elements sit within the 5’ noncoding regions of bacterial messenger RNAs (mRNA) and regulate an mRNA’s own transcription or translation, depending on the switch’s conformation. In the case of a transcription-regulating riboswitch, for example, association of the switch with a particular ligand, such as a metabolite, can alter the switch’s structure and in turn terminate transcription.
If Nature evolved anything that regulates energy-dependent RNA-mediated gene expression, it would first need to evolve the G protein-coupled receptors (GPCRs) that link the nutrient-dependent pheromone-controlled physiology of reproduction in yeasts to epigenetic imprinting in bacteria via chemotaxis and phototaxis. If chemotaxis and phototaxis are energy-dependent, Nature did not evolve anything. The de novo creation of GPCRs links the sun’s anti-entropic virucidal energy to protection of organized genomes from virus-driven energy theft and genomic entropy. The researcher’s screen identified the bacterial riboswitch that links the innate immune system to epigenetically-effected mRNA transcription and all energy-dependent cell type differentiation via the physiology of reproduction and supercoiled DNA in all living genera.