Publications by authors named "Lagha M"

Morphogen gradients convey essential spatial information during tissue patterning. While both concentration and timing of morphogen exposure are crucial, how cells interpret these graded inputs remains challenging to address. We employed an optogenetic system to acutely and reversibly modulate the nuclear concentration of the morphogen Dorsal (DL), homologue of NF-κB, which orchestrates dorso-ventral patterning in the embryo.

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Many biological and medical questions can be modeled using time-to-event data in finite-state Markov chains, with the phase-type distribution describing intervals between events. We solve the inverse problem: given a phase-type distribution, can we identify the transition rate parameters of the underlying Markov chain? For a specific class of solvable Markov models, we show this problem has a unique solution up to finite symmetry transformations, and we outline a recursive method for computing symbolic solutions for these models across any number of states. Using the Thomas decomposition technique from computer algebra, we further provide symbolic solutions for any model.

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Live imaging of translation based on tag recognition by a single-chain antibody is a powerful technique to assess translation regulation in living cells. However, this approach is challenging and requires optimization in terms of expression level and detection sensitivity of the system, especially in a multicellular organism. Here, we improved existing fluorescent tools and developed new ones to image and quantify nascent translation in the living embryo and in mammalian cells.

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In recent years, the technological landscape has undergone a profound metamorphosis catalyzed by the widespread integration of drones across diverse sectors. Essential to the drone manufacturing process is comprehensive testing, typically conducted in controlled laboratory settings to uphold safety and privacy standards. However, a formidable challenge emerges due to the inherent limitations of GPS signals within indoor environments, posing a threat to the accuracy of drone positioning.

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Biomolecular condensates organize biochemical processes at the subcellular level and can provide spatiotemporal regulation within a cell. Among these, ribonucleoprotein (RNP) granules are storage hubs for translationally repressed mRNA. Whether RNP granules can also activate translation and how this could be achieved remains unclear.

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Objectives: The aims of our study were to assess the sexual function in men with bipolar disorder type 1 in remission and to determine the various sociodemographic, clinical and therapeutic factors associated with sexual dysfunction.

Methods: We conducted a cross-sectional study over an 18-month period (January 2020-June 2021) in which we included men followed up for bipolar disorder type 1 in the euthymic phase strictly defined by a score <8 on the Young Mania Rating Scale and a score ≤7 on the Hamilton Depression Rating Scale. Sexual function was assessed using the Arizona Sexual Experiences Scale (Asex) in its Arabic-validated version.

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Imaging experiments reveal the complex and dynamic nature of the transcriptional hubs associated with Notch signaling.

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Monitoring transcription in living cells gives access to the dynamics of this complex fundamental process. It reveals that transcription is discontinuous, whereby active periods (bursts) are separated by one or several types of inactive periods of distinct lifetimes. However, decoding temporal fluctuations arising from live imaging and inferring the distinct transcriptional steps eliciting them is a challenge.

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In IoT environments, voluminous amounts of data are produced every single second. Due to multiple factors, these data are prone to various imperfections, they could be uncertain, conflicting, or even incorrect leading to wrong decisions. Multisensor data fusion has proved to be powerful for managing data coming from heterogeneous sources and moving towards effective decision-making.

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Recent developments in unmanned aerial vehicles (UAVs) have led to the introduction of a wide variety of innovative applications, especially in the Mobile Edge Computing (MEC) field. UAV swarms are suggested as a promising solution to cope with the issues that may arise when connecting Internet of Things (IoT) applications to a fog platform. We are interested in a crucial aspect of designing a swarm of UAVs in this work, which is the coordination of swarm agents in complicated and unknown environments.

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Lateral luxation is defined as a traumatic displacement of a tooth in any direction other than axially. A laterally luxated tooth is often immobile because of its bony lock. It produces a high metallic sound during percussion.

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To maintain cellular identities during development, gene expression profiles must be faithfully propagated through cell generations. The reestablishment of gene expression patterns upon mitotic exit is mediated, in part, by transcription factors (TF) mitotic bookmarking. However, the mechanisms and functions of TF mitotic bookmarking during early embryogenesis remain poorly understood.

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Genes are expressed in stochastic transcriptional bursts linked to alternating active and inactive promoter states. A major challenge in transcription is understanding how promoter composition dictates bursting, particularly in multicellular organisms. We investigate two key Drosophila developmental promoter motifs, the TATA box (TATA) and the Initiator (INR).

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Article Synopsis
  • Researchers have used the SunTag method to visualize and measure the translation of single mRNAs into proteins in living embryos.
  • The study specifically focuses on the mRNA translation of the protein Twist, which is important for cell development, revealing differences in translation efficiency across different regions.
  • The findings highlight the presence of "translation factories" where clustered mRNAs are co-translated, providing insights into how gene regulation occurs during organism development.
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Ribonucleoprotein (RNP) granules are dynamic condensates enriched in regulatory RNA binding proteins (RBPs) and RNAs under tight spatiotemporal control. Extensive recent work has investigated the molecular principles underlying RNP granule assembly, unraveling that they form through the self-association of RNP components into dynamic networks of interactions. How endogenous RNP granules respond to external stimuli to regulate RNA fate is still largely unknown.

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Objectives: This work aimed to estimate the knowledge and practice of general dentists in the governorate of Manouba regarding the management of patients at risk of infective endocarditis.

Materials And Methods: A survey involving private sector general dentists in the governorate of Manouba was performed. It contained 21 questions, and it was addressed to 111 dentists.

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Acquisition of cell fate is thought to rely on the specific interaction of remote cis-regulatory modules (CRMs), for example, enhancers and target promoters. However, the precise interplay between chromatin structure and gene expression is still unclear, particularly within multicellular developing organisms. In the present study, we employ Hi-M, a single-cell spatial genomics approach, to detect CRM-promoter looping interactions within topologically associating domains (TADs) during early Drosophila development.

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Motivation: During development, progenitor cells undergo multiple rounds of cellular divisions during which transcriptional programs must be faithfully propagated. Investigating the timing of transcriptional activation, which is a highly stochastic phenomenon, requires the analysis of large amounts of data. In order to perform automatic image analysis of transcriptional activation, we developed a software that segments and tracks both small and large objects, leading the user from raw data up to the results in their final form.

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With its rapid development, ease of collection, and the presence of a unique layer of nuclei located close to the surface, the Drosophila syncytial embryo is ideally suited to study the establishment of gene expression patterns during development. Recent improvements in RNA labeling technologies and confocal microscopy allow for visualizing gene activation and quantifying transcriptional dynamics in living Drosophila embryos. Here we review the available tools for mRNA fluorescent labeling and detection in live embryos and precisely describe the overall procedure, from design to mounting and confocal imaging.

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Eukaryotic chromosomes are organized in multiple scales, from nucleosomes to chromosome territories. Recently, genome-wide methods identified an intermediate level of chromosome organization, topologically associating domains (TADs), that play key roles in transcriptional regulation. However, these methods cannot directly examine the interplay between transcriptional activation and chromosome architecture while maintaining spatial information.

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The original version of this Article contained an error in Fig. 4a, in which the "=" sign of the equation was inadvertently replaced with a "-" sign. This has been corrected in the PDF and HTML versions of the Article.

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Pioneer transcription factors can engage nucleosomal DNA, which leads to local chromatin remodeling and to the establishment of transcriptional competence. However, the impact of enhancer priming by pioneer factors on the temporal control of gene expression and on mitotic memory remains unclear. Here we employ quantitative live imaging methods and mathematical modeling to test the effect of the pioneer factor Zelda on transcriptional dynamics and memory in Drosophila embryos.

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During development, transcriptional properties of progenitor cells are stably propagated across multiple cellular divisions. Yet, at each division, chromatin faces structural constraints imposed by the important nuclear re-organization operating during mitosis. It is now clear that not all transcriptional regulators are ejected during mitosis, but rather that a subset of transcription factors, chromatin regulators and epigenetic histone marks are able to 'bookmark' specific loci, thereby providing a mitotic memory.

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