1,132 research outputs found
Recommended from our members
Dissecting the regulatory strategies of NF-kB RelA target genes in the inflammatory response reveals differential transactivation logics
Nuclear factor κB (NF-κB) RelA is the potent transcriptional activator of inflammatory response genes. We stringently defined a list of direct RelA target genes by integrating physical (chromatin immunoprecipitation sequencing [ChIP-seq]) and functional (RNA sequencing [RNA-seq] in knockouts) datasets. We then dissected each gene’s regulatory strategy by testing RelA variants in a primary-cell genetic-complementation assay. All endogenous target genes require RelA to make DNA-base-specific contacts, and none are activatable by the DNA binding domain alone. However, endogenous target genes differ widely in how they employ the two transactivation domains. Through model-aided analysis of the dynamic time-course data, we reveal the gene-specific synergy and redundancy of TA1 and TA2. Given that post-translational modifications control TA1 activity and intrinsic affinity for coactivators determines TA2 activity, the differential TA logics suggests context-dependent versus context-independent control of endogenous RelA-target genes. Although some inflammatory initiators appear to require co-stimulatory TA1 activation, inflammatory resolvers are a part of the NF-κB RelA core response
A method for measuring the Neel relaxation time in a frozen ferrofluid
We report a novel method of determining the average Neel relaxation time and
its temperature dependence by calculating derivatives of the measured time
dependence of temperature for a frozen ferrofluid exposed to an alternating
magnetic field. The ferrofluid, composed of dextran-coated Fe3O4 nanoparticles
(diameter 13.7 nm +/- 4.7 nm), was synthesized via wet chemical precipitation
and characterized by x-ray diffraction and transmission electron microscopy. An
alternating magnetic field of constant amplitude (H0 = 20 kA/m) driven at
frequencies of 171 kHz, 232 kHz and 343 kHz was used to determine the
temperature dependent magnetic energy absorption rate in the temperature range
from 160 K to 210 K. We found that the specific absorption rate of the
ferrofluid decreased monotonically with temperature over this range at the
given frequencies. From these measured data, we determined the temperature
dependence of the Neel relaxation time and estimate a room-temperature
magnetocrystalline anisotropy constant of 40 kJ/m3, in agreement with
previously published results
- …