37 research outputs found
Relationship between Occupational Stress and Work-related Musculoskeletal Disorders in Korean Male Firefighters
Arabidopsis HDA6 Regulates Locus-Directed Heterochromatin Silencing in Cooperation with MET1
Heterochromatin silencing is pivotal for genome stability in eukaryotes. In
Arabidopsis, a plant-specific mechanism called
RNA–directed DNA methylation (RdDM) is involved in heterochromatin
silencing. Histone deacetylase HDA6 has been identified as a component of such
machineries; however, its endogenous targets and the silencing mechanisms have
not been analyzed globally. In this study, we investigated the silencing
mechanism mediated by HDA6. Genome-wide transcript profiling revealed that the
loci silenced by HDA6 carried sequences corresponding to the RDR2-dependent
24-nt siRNAs, however their transcript levels were mostly unaffected in the
rdr2 mutant. Strikingly, we observed significant overlap of
genes silenced by HDA6 to those by the CG DNA methyltransferase MET1.
Furthermore, regardless of dependence on RdDM pathway, HDA6 deficiency resulted
in loss of heterochromatic epigenetic marks and aberrant enrichment for
euchromatic marks at HDA6 direct targets, along with ectopic expression of these
loci. Acetylation levels increased significantly in the hda6
mutant at all of the lysine residues in the H3 and H4 N-tails, except H4K16.
Interestingly, we observed two different CG methylation statuses in the
hda6 mutant. CG methylation was sustained in the
hda6 mutant at some HDA6 target loci that were surrounded
by flanking DNA–methylated regions. In contrast, complete loss of CG
methylation occurred in the hda6 mutant at the HDA6 target loci
that were isolated from flanking DNA methylation. Regardless of CG methylation
status, CHG and CHH methylation were lost and transcriptional derepression
occurred in the hda6 mutant. Furthermore, we show that HDA6
binds only to its target loci, not the flanking methylated DNA, indicating the
profound target specificity of HDA6. We propose that HDA6 regulates
locus-directed heterochromatin silencing in cooperation with MET1, possibly
recruiting MET1 to specific loci, thus forming the foundation of silent
chromatin structure for subsequent non-CG methylation
Psychological factors influence the gastroesophageal reflux disease (GERD) and their effect on quality of life among firefighters in South Korea
The association between long working hours and the metabolic syndrome: evidences from the 5th Korean National Health and Nutrition Examination Survey of 2010 and 2012
Smoking and bone mineral density: comprehensive analyses of the third National Health and Nutrition Examination Survey (NHANES III)
Nationwide firefighter survey: the prevalence of lower back pain and its related psychological factors among Korean firefighters
Industry dynamics with knowledge-based competition: a computational study of entry and exit patterns
Industry dynamics, Shakeouts, Innovation, Imitation, Agent-based computational model, L10, O30,
A stepwise 2′-hydroxyl activation mechanism for the bacterial transcription termination factor Rho helicase
International audienceThe bacterial Rho factor is a ring-shaped ATP-dependent helicase that tracks along RNA transcripts and disrupts RNA-DNA duplexes and transcription complexes in its path. Using combinatorial nucleotide analog interference mapping (NAIM), we explore the topology and dynamics of functional Rho-RNA complexes and reveal the RNA-dependent stepping mechanism of Rho helicase. Periodic Gaussian distributions of NAIM signals show that Rho forms uneven productive interactions with the track nucleotides and disrupts RNA-DNA duplexes in a succession of large(similar to 7-nucleotide-long) discrete steps triggered by 2'-hydroxyl activation events. This periodic 2'-OH-dependent activation does not depend on the RNA-DNA pairing energy but is finely tuned by sequence-dependent interactions with the RNA track. These features explain the strict RNA specificity and contextual efficiency of the enzyme and provide a new paradigm for conditional tracking by a helicase ring