Search results for "Gene Expression"

Discovering new proteins in plant mitochondria by RNA editing simulation

2016

In plant mitochondria an essential mechanism for gene expression is RNA editing, often influencing the synthesis of functional proteins. RNA editing alters the linearity of genetic information transfer. Indeed it causes differences between RNAs and their coding DNA sequences that hinder both experimental and computational research of genes. Therefore common software tools for gene search, successfully applied to find canonical genes, often fail in discovering genes encrypted in the genome of plants. Here we propose a novel strategy useful to identify candidate coding sequences resulting from possible editing substitutions. In particular, we consider c!u substitutions leading to the creation…

Model-based design of RNA hybridization networks implemented in living cells

2017

[EN] Synthetic gene circuits allow the behavior of living cells to be reprogrammed, and non-coding small RNAs (sRNAs) are increasingly being used as programmable regulators of gene expression. However, sRNAs (natural or synthetic) are generally used to regulate single target genes, while complex dynamic behaviors would require networks of sRNAs regulating each other. Here, we report a strategy for implementing such networks that exploits hybridization reactions carried out exclusively by multifaceted sRNAs that are both targets of and triggers for other sRNAs. These networks are ultimately coupled to the control of gene expression. We relied on a thermo-dynamic model of the different stable…

Chromatin Immunoprecipitation Assay to Identify Genomic Binding Sites of Regulatory Factors

2016

DNA-protein interactions are vital to fundamental cellular events including transcription, replication, DNA repair, and recombination. Thus, their study holds the key to our understanding of mechanisms underlying normal development and homeostasis as well as disease. Transcriptional regulation is a highly complex process that involves recruitment of numerous factors resulting in formation of multi-protein complexes at gene promoters to regulate gene expression. The studied proteins can be, for example, transcription factors, epigenetic regulators, co-activators, co-repressors, or ligand-activated nuclear receptors as estrogen receptor-α (ERα) bound either directly to the DNA or indirectly b…

2018

Aging is a multi-factorial process, where epigenetic factors play one of the major roles in declines of gene expression and organic function. DNA methylation at CpG islands of promoters can directly change the expression of the neighbouring gene mostly through inhibition. Furthermore, it is known that DNA methylation patterns change during aging In our study, we investigated gene regulation through DNA methylation of genes up- and downregulated in long-lived people compared to a younger cohort. Our data revealed that comparatively highly methylated genes were associated with high expression in long-lived people (e.g. over 85). Genes with lower levels of methylation were associated with low …

Temperature-responsive miRNAs in Drosophila orchestrate adaptation to different ambient temperatures

2017

The majority of Drosophila genes are expressed in a temperature-dependent manner, but the way in which small RNAs may contribute to this effect is completely unknown as we currently lack an idea of how small RNA transcriptomes change as a function of temperature. Applying high-throughput sequencing techniques complemented by quantitative real-time PCR experiments, we demonstrate that altered ambient temperature induces drastic but reversible changes in sequence composition and total abundance of both miRNA and piRNA populations. Further, mRNA sequencing reveals that the expression of miRNAs and their predicted target transcripts correlates inversely, suggesting that temperature-responsive m…

T-Box Genes in Drosophila Limb Development

2017

T-box genes are essential for limb development in vertebrates and arthropods. The Drosophila genome encodes eight T-box genes, six of which are expressed in limb ontogenesis. The Tbx20-related gene pair midline and H15 is essential for dorso-ventral patterning of the Drosophila legs. The three Tbx6-related Dorsocross genes are required for epithelial remodeling during wing development. The Drosophila gene optomotor-blind (omb) is the only member of the Tbx2 subfamily in the fly and is predominantly involved in wing development. Omb is essential for wing development and is sufficient to promote the development of a second wing pair. Targeted manipulations of omb expression have shown that th…

miR-22 suppresses DNA ligase III addiction in multiple myeloma

2019

Multiple myeloma (MM) is a hematologic malignancy characterized by high genomic instability. Here we provide evidence that hyper-activation of DNA ligase III (LIG3) is crucial for genomic instability and survival of MM cells. LIG3 mRNA expression in MM patients correlates with shorter survival and even increases with more advanced stage of disease. Knockdown of LIG3 impairs MM cells viability in vitro and in vivo, suggesting that neoplastic plasmacells are dependent on LIG3-driven repair. To investigate the mechanisms involved in LIG3 expression, we investigated the post-transcriptional regulation. We identified miR-22-3p as effective negative regulator of LIG3 in MM. Enforced expression of…

From “Cellular” RNA to “Smart” RNA: Multiple Roles of RNA in Genome Stability and Beyond

2018

Coding for proteins has been considered the main function of RNA since the "central dogma" of biology was proposed. The discovery of noncoding transcripts shed light on additional roles of RNA, ranging from the support of polypeptide synthesis, to the assembly of subnuclear structures, to gene expression modulation. Cellular RNA has therefore been recognized as a central player in often unanticipated biological processes, including genomic stability. This ever-expanding list of functions inspired us to think of RNA as a "smart" phone, which has replaced the older obsolete "cellular" phone. In this review, we summarize the last two decades of advances in research on the interface between RNA…

FANCD2 modulates the mitochondrial stress response to prevent common fragile site instability

2021

Common fragile sites (CFSs) are genomic regions frequently involved in cancer-associated rearrangements. Most CFSs lie within large genes, and their instability involves transcription- and replication-dependent mechanisms. Here, we uncover a role for the mitochondrial stress response pathway in the regulation of CFS stability in human cells. We show that FANCD2, a master regulator of CFS stability, dampens the activation of the mitochondrial stress response and prevents mitochondrial dysfunction. Genetic or pharmacological activation of mitochondrial stress signaling induces CFS gene expression and concomitant relocalization to CFSs of FANCD2. FANCD2 attenuates CFS gene transcription and pr…

Exome-Wide Association Study on Alanine Aminotransferase Identifies Sequence Variants in the GPAM and APOE Associated With Fatty Liver Disease.

2021

BACKGROUND & AIMS: Fatty liver disease (FLD) is a growing epidemic that is expected to be the leading cause of end-stage liver disease within the next decade. Both environmental and genetic factors contribute to the susceptibility of FLD. Several genetic variants contributing to FLD have been identified in exome-wide association studies. However, there is still a missing hereditability indicating that other genetic variants are yet to be discovered. METHODS: To find genes involved in FLD, we first examined the association of missense and nonsense variants with alanine amino transferase at an exome-wide level in 425,671 participants from the UK Biobank. We then validated genetic variants wit…