Project description:Cross-Palaearctic population connectivity in a migratory shorebird, the Common Redshank (Tringa totanus), defies high site fidelity
| PRJNA1059529 | ENA
Project description:Cross‐decades stability of an avian hybrid zone
Project description:Discovery of common Asian copy number variants using a novel integrated high-resolution array CGH and massively parallel DNA sequencing. We attempted to discover common Asian copy number variants (CNVs) from the DNA of 30 Asian women (10 Korean, 10 CHB (HapMap), 10 JPT (HapMap)) using a custom-designed 24M-oligonucleotide Agilent platform (1.1M X 24 slides). The reference sample for aCGH was NA10851 (HapMap CEPH). In addition to the 30 women, 3 more individuals were analyzed as controls (AK1 (Kim, J.I. et al., 2009 Nature), NA12878 and NA19240).
Project description:Migration is essential for the reproduction and survival of many animals, yet little is understood about its underlying molecular mechanisms. We used the salmonid Oncorhynchus mykiss to gain mechanistic insight into smoltification, which is a morphological, physiological, and behavioral transition undertaken by some juveniles that culminates in a seaward migration. This species is experimentally tractable and, unlike common model species, displays intra- and inter-population variation in migration propensity. Migratory individuals can produce non-migratory progeny and vice versa, indicating a high degree of phenotypic plasticity. One potential way that phenotypic plasticity might be linked to variation in migration-related life history tactics is through epigenetic regulation of gene expression. To explore this, we quantitatively measured genome-scale DNA methylation in fin tissue using reduced representation bisulfite sequencing of F2 siblings produced from a cross between steelhead (migratory) and rainbow trout (non-migratory) lines. We identified 57 differentially methylated regions (DMRs) between smolt and resident O. mykiss juveniles. DMRs were of high magnitude, ranging from 20-62% differential methylation between life history types, and over half of the gene-associated DMRs were in transcriptional regulatory regions. Many of the DMRs encode proteins with activity relevant to migration-related transitions (e.g. circadian rhythm pathway, nervous system development, protein kinase activity). This study provides the first evidence of a relationship between epigenetic variation and life history divergence associated with a migration-related transition in any species. Comparing global DNA methyldation profiles (via RRBS) of resident and smolt O. mykiss siblings using caudal fin tissue.
Project description:Methylation of CG dinucleotides (mCG), which regulates genome function in eukaryotes, is epigenetically propagated by Dnmt1/MET1 methyltransferases via a semiconservative mechanism. How these enzymes accomplish stable epigenetic inheritance despite imperfect fidelity remains mysterious. Here we show that MET1 de novo activity, which is enhanced by existing proximate methylation, seeds and stabilizes mCG in Arabidopsis thaliana genes. MET1 activity is delimited by active DNA demethylation and counterbalanced by histone variant H2A.Z, natural variation in which accounts for high genic methylation in accessions from northern Sweden. Based on these observations, we develop a mathematical model that precisely recapitulates mCG inheritance dynamics and successfully predicts steady-state intragenic mCG patterns and their population-scale variation given only CG site spacing as input. Our results demonstrate how methylation patterns are created in plant genes, reconcile imperfect mCG maintenance with long-term stability, and establish a quantitative model for the epigenetic inheritance of mCG.
Project description:MicF is a textbook example of a small regulatory RNA (sRNA) that acts on a trans-encoded target mRNA through imperfect base paring. The discovery of MicF as a post-transcriptional repressor of the major Escherichia coli porin OmpF established the paradigm for a meanwhile common mechanism of translational inhibition, through antisense sequestration of a ribosome binding site. However, whether MicF regulates additional genes has remained unknown for almost three decades. Here, we have harnessed the novel superfolder variant of GFP for reporter-gene fusions to validate newly predicted targets of MicF in Salmonella. We show that the conserved 5’ end of MicF acts by seed pairing to repress the mRNAs of global transcriptional regulator Lrp, periplasmic protein YahO, and lipid A-modifying enzyme LpxR. Whilst MicF binds lrp and yahO in the 5’ UTR, it targets lpxR at both the ribosome binding site and deep within the coding sequence. Repression in the coding sequence of lpxR may be achieved by decreasing mRNA stability through exacerbating the use of a native RNase E site proximal to the short MicF-lpxR duplex. Altogether, this study assigns the classic MicF sRNA to the growing class of Hfqassociated regulators that use diverse mechanisms to impact multiple loci.
2012-02-17 | GSE35848 | GEO
Project description:Gut microbiome dynamics during pre-migratory fattening in a long-distance migratory bird
Project description:MicF is a textbook example of a small regulatory RNA (sRNA) that acts on a trans-encoded target mRNA through imperfect base paring. The discovery of MicF as a post-transcriptional repressor of the major Escherichia coli porin OmpF established the paradigm for a meanwhile common mechanism of translational inhibition, through antisense sequestration of a ribosome binding site. However, whether MicF regulates additional genes has remained unknown for almost three decades. Here, we have harnessed the novel superfolder variant of GFP for reporter-gene fusions to validate newly predicted targets of MicF in Salmonella. We show that the conserved 5’ end of MicF acts by seed pairing to repress the mRNAs of global transcriptional regulator Lrp, periplasmic protein YahO, and lipid A-modifying enzyme LpxR. Whilst MicF binds lrp and yahO in the 5’ UTR, it targets lpxR at both the ribosome binding site and deep within the coding sequence. Repression in the coding sequence of lpxR may be achieved by decreasing mRNA stability through exacerbating the use of a native RNase E site proximal to the short MicF-lpxR duplex. Altogether, this study assigns the classic MicF sRNA to the growing class of Hfqassociated regulators that use diverse mechanisms to impact multiple loci. To determine the targets of the small regulatory RNA MicF in S. Typhimurium, we looked at the effect of a short pulse of MicF over-expression on the Salmonella transcriptome. To achieve over-expression, the micF gene was cloned in the pBAD plasmid and induced with 0.2% L-arabinose for 10 min. We then extracted the total RNA for transcriptional profiling. A strain carrying the pBAD plasmid w/o insert was used as negative control (also induced by L-arabinose). 3 biological replicates were performed. This sRNA target identification strategy has been described in Papenfort et al; Molecular Microbiology (2006) 62(6), 1674?1688.
Project description:The embryonic site of definitive hematopoietic stem cell (dHSC) origination has been debated for decades. Although an intra-embryonic origin is supported, recent data suggest that a large fraction of adult blood derives from the yolk sac (YS). Investigating the origins of hematopoiesis before heartbeat onset (i.e. 5-7 somite pairs (sp)) is precluded by a lack of assays that can distinguish dHSC precursors in early embryos. Here, we report robust, multi-lineage and serially transplantable dHSC activity from cultured 2-7sp murine embryonic explants (Em-Ex). dHSC were undetectable in 2-7sp YS explants (YS-Ex). Our work supports a model in which the embryo, not the YS, is the major source of lifelong hematopoiesis.
2018-11-13 | GSE110909 | GEO
Project description:Long-term warming (forty-decades) shaped the keystone microbial community