126 research outputs found
c-Jun NH2-terminal Kinase Promotes Apoptosis by Down-Regulating the Transcriptional Co-repressor CtBP
Genetic knock out of the transcriptional co-repressor carboxyl-terminal-binding protein (CtBP) in mouse embryonic fibroblasts results in up-regulation of several genes involved in apoptosis. We predicted, therefore, that a propensity toward apoptosis might be regulated through changes in cellular CtBP levels. Previously, we have identified the homeodomain-interacting protein kinase 2 as such a regulator and demonstrated that HIPK2 activation causes Ser-422 phosphorylation and degradation of CtBP. In this study, we found that c-Jun NH2-terminal kinase 1 activation triggered CtBP phosphorylation on Ser-422 and subsequent degradation, inducing p53-independent apoptosis in human lung cancer cells. JNK1 has previously been linked to UV-directed apoptosis. Expression of MKK7-JNK1 or exposure to UV irradiation reduced cellular levels of CtBP via a proteasome-mediated pathway. This effect was prevented by JNK1 deficiency. In addition, sustained activation of the JNK1 pathway by cisplatin similarly triggered CtBP degradation. These findings provide a novel target for chemotherapy in cancers lacking p53
DiffusionVMR: Diffusion Model for Video Moment Retrieval
Video moment retrieval is a fundamental visual-language task that aims to
retrieve target moments from an untrimmed video based on a language query.
Existing methods typically generate numerous proposals manually or via
generative networks in advance as the support set for retrieval, which is not
only inflexible but also time-consuming. Inspired by the success of diffusion
models on object detection, this work aims at reformulating video moment
retrieval as a denoising generation process to get rid of the inflexible and
time-consuming proposal generation. To this end, we propose a novel
proposal-free framework, namely DiffusionVMR, which directly samples random
spans from noise as candidates and introduces denoising learning to ground
target moments. During training, Gaussian noise is added to the real moments,
and the model is trained to learn how to reverse this process. In inference, a
set of time spans is progressively refined from the initial noise to the final
output. Notably, the training and inference of DiffusionVMR are decoupled, and
an arbitrary number of random spans can be used in inference without being
consistent with the training phase. Extensive experiments conducted on three
widely-used benchmarks (i.e., QVHighlight, Charades-STA, and TACoS) demonstrate
the effectiveness of the proposed DiffusionVMR by comparing it with
state-of-the-art methods
Evolution of KChIP2 Gene Function is Localized Within the Core Promoter and 5’ UTR
Plan des Kaufs der A. Voemelschen Buchhandlung, Leipzi
UniVTG: Towards Unified Video-Language Temporal Grounding
Video Temporal Grounding (VTG), which aims to ground target clips from videos
(such as consecutive intervals or disjoint shots) according to custom language
queries (e.g., sentences or words), is key for video browsing on social media.
Most methods in this direction develop taskspecific models that are trained
with type-specific labels, such as moment retrieval (time interval) and
highlight detection (worthiness curve), which limits their abilities to
generalize to various VTG tasks and labels. In this paper, we propose to Unify
the diverse VTG labels and tasks, dubbed UniVTG, along three directions:
Firstly, we revisit a wide range of VTG labels and tasks and define a unified
formulation. Based on this, we develop data annotation schemes to create
scalable pseudo supervision. Secondly, we develop an effective and flexible
grounding model capable of addressing each task and making full use of each
label. Lastly, thanks to the unified framework, we are able to unlock temporal
grounding pretraining from large-scale diverse labels and develop stronger
grounding abilities e.g., zero-shot grounding. Extensive experiments on three
tasks (moment retrieval, highlight detection and video summarization) across
seven datasets (QVHighlights, Charades-STA, TACoS, Ego4D, YouTube Highlights,
TVSum, and QFVS) demonstrate the effectiveness and flexibility of our proposed
framework. The codes are available at https://github.com/showlab/UniVTG.Comment: Accepted by ICCV 2023. 16 pages, 10 figures, 13 tables. Code:
https://github.com/showlab/UniVT
Coherent Dynamics of Charge Carriers in {\gamma}-InSe Revealed by Ultrafast Spectroscopy
For highly efficient ultrathin solar cells, layered indium selenide (InSe), a
van der Waals solid, has shown a great promise. In this paper, we study the
coherent dynamics of charge carriers generation in {\gamma}-InSe single
crystals. We employ ultrafast transient absorption spectroscopy to examine the
dynamics of hot electrons after resonant photoexcitation. To study the effect
of excess kinetic energy of electrons after creating A exciton (VB1 to CB
transition), we excite the sample with broadband pulses centered at 600, 650,
700 and 750 nm, respectively. We analyze the relaxation and recombination
dynamics in {\gamma}-InSe by global fitting approach. Five decay associated
spectra with their associated lifetimes are obtained, which have been assigned
to intraband vibrational relaxation and interband recombination processes. We
extract characteristic carrier thermalization times from 1 to 10 ps. To examine
the coherent vibrations accompanying intraband relaxation dynamics, we analyze
the kinetics by fitting to exponential functions and the obtained residuals are
further processed for vibrational analysis. A few key phonon coherences are
resolved and ab-initio quantum calculations reveal the nature of the associated
phonons. The wavelet analysis is employed to study the time evolution of the
observed coherences, which show that the low-frequency coherences last for more
than 5 ps. Associated calculations reveal that the contribution of the
intralayer phonon modes is the key determining factor for the scattering
between free electrons and lattice. Our results provide fundamental insights
into the photophysics in InSe and help to unravel their potential for
high-performance optoelectronic devices
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Precise temporal regulation of alternative splicing during neural development
Alternative splicing (AS) is one crucial step of gene expression that must be tightly regulated during neurodevelopment. However, the precise timing of developmental splicing switches and the underlying regulatory mechanisms are poorly understood. Here we systematically analyze the temporal regulation of AS in a large number of transcriptome profiles of developing mouse cortices, in vivo purified neuronal subtypes, and neurons differentiated in vitro. Our analysis reveals early-switch and late-switch exons in genes with distinct functions, and these switches accurately define neuronal maturation stages. Integrative modeling suggests that these switches are under direct and combinatorial regulation by distinct sets of neuronal RNA-binding proteins including Nova, Rbfox, Mbnl, and Ptbp. Surprisingly, various neuronal subtypes in the sensory systems lack Nova and/or Rbfox expression. These neurons retain the “immature” splicing program in early-switch exons, affecting numerous synaptic genes. These results provide new insights into the organization and regulation of the neurodevelopmental transcriptome
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