PRISMA and BioID disclose a motifs-based interactome of the intrinsically disordered transcription factor C/EBPα.

C/EBPα represents a paradigm intrinsically disordered transcription factor containing short linear motifs and post-translational modifications (PTM). Unraveling C/EBPα protein interaction networks is a prerequisite for understanding the multi-modal functions of C/EBPα in hematopoiesis and leukemia. Here, we combined arrayed peptide matrix screening (PRISMA) with BioID to generate an in vivo validated and isoform specific interaction map of C/EBPα. The myeloid C/EBPα interactome comprises promiscuous and PTM-regulated interactions with protein machineries involved in gene expression, epigenetics, genome organization, DNA replication, RNA processing, and nuclear transport. C/EBPα interaction hotspots coincide with homologous conserved regions of the C/EBP family that also score as molecular recognition features. PTMs alter the interaction spectrum of C/EBP-motifs to configure a multi-valent transcription factor hub that interacts with multiple co-regulatory components, including BAF/SWI-SNF or Mediator complexes. Combining PRISMA and BioID is a powerful strategy to systematically explore the PTM-regulated interactomes of intrinsically disordered transcription factors.

A laser photoacoustic analysis of residual CO2 and H2O in larch stems.

Every so often, the results obtained from investigations into the effects of varying environmental conditions on the tree growth rate at the same sites and on the change in the carbon balance in plants, using traditional methods, are found to differ widely. We believe that the reason for the ambiguity of the data has to do with failure to account for the role of the residual CO2 (and H2O) in the tree wood exhibiting a climate response. In our earlier work, the results of a laser photoacoustic gas analysis of CO2 and H2O vacuum-desorbed from disc tree rings of evergreen conifer trees were presented. In this paper, laser photoacoustic measurements of tree ring gases in deciduous conifer trees and CO2 carbon isotope composition determined by means of a mass spectrometer are given. Conclusions are made regarding the response of annual larch CO2 disc tree ring distributions to climatic parameters (temperatures and precipitation). The data about the CO2 disc content for different sites are compared.

Laser photoacoustic detection of CO2 in old disc tree-rings.

A homemade CO2-laser photoacoustic spectrometer has been used for monitoring CO2 in gas samples extracted under vacuum from the wood of old spruce disc tree-rings for a ∼60 year series. The experimental results show that (1) the CO2 concentration exhibits annual trends correlated with an increase in atmospheric CO2 in a number of cases; (2) at the time when the annual CO2 trend changes from positive to negative, the annual tree-ring stable carbon isotope ratios (δ13C) of CO2 change as well; (3) the disc tree-ring widths are observed to decrease in most cases where the annual CO2 increased; (4) simultaneously with the annual CO2 variation, annual H2O distribution was detected in gas samples of the wood tree-rings of one spruce disc. The observed patterns of the annual CO2 distribution in the disc tree-rings are assumed to be the evidence of the impact of the atmospheric CO2 increase. In other words, a change in the concentration gradient between the stem and the atmospheric CO2 may lead to a gradual CO2 accumulation in the stem because of a decrease in the diffusion rate and to a change in the tree parameters.