431 research outputs found
Control of Cotton Fibre Elongation by a Homeodomain Transcription Factor GhHOX3
Cotton fibres are unusually long, single-celled epidermal seed trichomes and a model for plant cell growth, but little is known about the regulation of fibre cell elongation. Here we report that a homeodomain-leucine zipper (HD-ZIP) transcription factor, GhHOX3, controls cotton fibre elongation. GhHOX3 genes are localized to the 12th homoeologous chromosome set of allotetraploid cotton cultivars, associated with quantitative trait loci (QTLs) for fibre length. Silencing of GhHOX3 greatly reduces (\u3e80%) fibre length, whereas its overexpression leads to longer fibre. Combined transcriptomic and biochemical analyses identify target genes of GhHOX3 that also contain the L1-box cis-element, including two cell wall loosening protein genes GhRDL1 and GhEXPA1. GhHOX3 interacts with GhHD1, another homeodomain protein, resulting in enhanced transcriptional activity, and with cotton DELLA, GhSLR1, repressor of the growth hormone gibberellin (GA). GhSLR1 interferes with the GhHOX3–GhHD1 interaction and represses target gene transcription. Our results uncover a novel mechanism whereby a homeodomain protein transduces GA signal to promote fibre cell elongation
Preferential regulation of stably expressed genes in the human genome suggests a widespread expression buffering role of microRNAs
In this study, we comprehensively explored the stably expressed genes (SE genes) and fluctuant genes (FL genes) in the human genome by a meta-analysis of large scale microarray data. We found that these genes have distinct function distributions. miRNA targets are shown to be significantly enriched in SE genes by using propensity analysis of miRNA regulation, supporting the hypothesis that miRNAs can buffer whole genome expression fluctuation. The expression-buffering effect of miRNA is independent of the target site number within the 3'-untranslated region. In addition, we found that gene expression fluctuation is positively correlated with the number of transcription factor binding sites in the promoter region, which suggests that coordination between transcription factors and miRNAs leads to balanced responses to external perturbations
The state of the Martian climate
60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes
Does or did the supernova remnant Cassiopeia A operate as a PeVatron?
For decades, supernova remnants (SNRs) have been considered the prime sources
of Galactic Cosmic rays (CRs). But whether SNRs can accelerate CR protons to
PeV energies and thus dominate CR flux up to the knee is currently under
intensive theoretical and phenomenological debate. The direct test of the
ability of SNRs to operate as CR PeVatrons can be provided by ultrahigh-energy
(UHE; ~TeV) -rays. In this context, the historical
SNR Cassiopeia A (Cas A) is considered one of the most promising target for UHE
observations. This paper presents the observation of Cas A and its vicinity by
the LHAASO KM2A detector. The exceptional sensitivity of LHAASO KM2A in the UHE
band, combined with the young age of Cas A, enabled us to derive stringent
model-independent limits on the energy budget of UHE protons and nuclei
accelerated by Cas A at any epoch after the explosion. The results challenge
the prevailing paradigm that Cas A-type SNRs are major suppliers of PeV CRs in
the Milky Way.Comment: 11 pages, 3 figures, Accepted by the APJ
Measurement of ultra-high-energy diffuse gamma-ray emission of the Galactic plane from 10 TeV to 1 PeV with LHAASO-KM2A
The diffuse Galactic -ray emission, mainly produced via interactions
between cosmic rays and the interstellar medium and/or radiation field, is a
very important probe of the distribution, propagation, and interaction of
cosmic rays in the Milky Way. In this work we report the measurements of
diffuse -rays from the Galactic plane between 10 TeV and 1 PeV
energies, with the square kilometer array of the Large High Altitude Air Shower
Observatory (LHAASO). Diffuse emissions from the inner
(, ) and outer
(, ) Galactic plane are detected with
and significance, respectively. The outer Galactic
plane diffuse emission is detected for the first time in the very- to
ultra-high-energy domain (~TeV). The energy spectrum in the inner Galaxy
regions can be described by a power-law function with an index of
, which is different from the curved spectrum as expected from
hadronic interactions between locally measured cosmic rays and the
line-of-sight integrated gas content. Furthermore, the measured flux is higher
by a factor of than the prediction. A similar spectrum with an index of
is found in the outer Galaxy region, and the absolute flux for
TeV is again higher than the prediction for hadronic
cosmic ray interactions. The latitude distributions of the diffuse emission are
consistent with the gas distribution, while the longitude distributions show
clear deviation from the gas distribution. The LHAASO measurements imply that
either additional emission sources exist or cosmic ray intensities have spatial
variations.Comment: 12 pages, 8 figures, 5 tables; accepted for publication in Physical
Review Letters; source mask file provided as ancillary fil
Upregulation of Circulating PD-L1/PD-1 Is Associated with Poor Post-Cryoablation Prognosis in Patients with HBV-Related Hepatocellular Carcinoma
BACKGROUND: The programmed cell death-1 receptor/programmed cell death-1 ligand (PD-1/PD-L1) pathway plays a crucial role in tumor evasion from host immunity. This study was designed to evaluate the association between circulating PD-L1/PD-1 and prognosis after cryoablation in patients with HBV-related hepatocellular carcinoma (HCC). METHODOLOGY/PRINCIPAL FINDINGS: In the present study, 141 HBV-related HCC patients were enrolled and of those 109 patients received cryoablation. Circulating PD-L1/PD-1 expression was tested by flow cytometry, and 23 patients were simultaneously evaluated for intratumoral PD-L1 expression by immunohistochemical staining. Circulating PD-1/PD-L1 expression was associated with severity of diseases in patients with HCC, and the circulating PD-L1 expression was closely correlated with intratumoral PD-L1 expression. Of the clinical parameters, PD-1/PD-L1 expression was associated with tumor size, blood vessel invasion and BCLC staging. Moreover, PD-1/PD-L1 expression dropped after cryoablation while being elevated at the time of tumor recurrence. Patients with higher expression of circulating PD-L1, as well as circulating PD-1, had a significantly shorter overall survival and tumor-free survival than those with lower expression. Multivariate analysis confirmed that circulating PD-L1 could serve as an independent predictor of overall survival and tumor-recurrence survival in HCC patients after cryoablation. CONCLUSIONS/SIGNIFICANCE: Upregulation of circulating PD-L1/PD-1 is associated with poor post-cryoablation prognosis in patients with HBV-related hepatocellular carcinoma
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