Trojan horse peptide conjugates remodel the activity spectrum of clinical antibiotics.

Infections caused by gram-negative pathogens continue to be a major risk to human health because of the innate antibiotic resistance endowed by their unique cell membrane architecture. Nature has developed an elegant solution to target gram-negative strains, namely by conjugating toxic antibiotic warheads to a suitable carrier to facilitate the active import of the drug to a specific target organism. Microcin C7 (McC) is a Trojan horse peptide-conjugated antibiotic that specifically targets enterobacteria by exploiting active import through oligopeptide transport systems.

Progress on molecular mechanisms of bacterial transcription termination.

Transcription is the process by which genetic information is copied from DNA to RNA, and it can be divided into three stages: transcription initiation, elongation, and termination. Transcription termination is the last step of gene transcription and is crucial for accurate gene expression. Two prevailing modes of transcription termination exist in bacteria: Rho-dependent termination and intrinsic termination (Rho-independent termination).

High-throughput capture of transcription factor-driven epigenome dynamics using PHILO ChIP-seq.

Assessing the dynamics of chromatin features and transcription factor (TF) binding at scale remains a significant challenge in plants. Here, we present PHILO (Plant HIgh-throughput LOw input) ChIP-seq, a high-throughput ChIP-seq platform that enables the cost-effective and extensive capture of TF binding and genome-wide distributions of histone modifications. The PHILO ChIP-seq pipeline is adaptable to many plant species, requires very little starting material (1mg), and provides the option to use MNase (micrococcal nuclease) for chromatin fragmentation.

Imaging of porphyrin-specific fluorescence in pathogenic bacteria using a wearable, hands-free system.

Fluorescence imaging is an effective method for detecting porphyrin production in bacteria, leveraging the natural fluorescence properties of porphyrins. Here we use a simple, lightweight, hands-free device for rapid, non-invasive assessments in clinical settings, microbial research, and diagnostic applications. Specifically in this study, we examined 15 bacterial and 2 fungal strains commonly associated with skin, oral, and/or multi-site infections at wound sites for their ability to autofluoresce based on their porphyrin production.

Characterizing the role of PP2A B'' family subunits in mechanical stress response and plant development through calcium and ABA signaling in Arabidopsis thaliana.

Protein phosphatase 2AB'' (PP2A B'') family subunits have calcium-binding EF-hand motifs, facilitating interaction with PP2A substrates. In Arabidopsis thaliana, the PP2A B'' family subunits consist of six members, AtB''α-ε and FASS. These subunits can interact with a basic leucine zipper transcription factor, VIP1, and its close homologs.

Total Synthesis of Marformycins A and D.

We report the synthesis of the antimicrobial cyclodepsipeptides marformycin A () and marformycin D () using a solid-phase approach. A scalable solution-phase synthesis of the γ-hydroxypiperazic acid subunit in , starting from -hydroxyproline, is also described. Structural analysis of and its Leu- congener demonstrates conformational differences that may underlie their divergent antimicrobial activities.

Contributions of the Dachsous intracellular domain to Dachsous-Fat signaling.

The protocadherins Fat and Dachsous regulate organ growth, shape, patterning, and planar cell polarity. Although Dachsous and Fat have been described as ligand and receptor, respectively, in a signal transduction pathway, there is also evidence for bidirectional signaling. Here, we assess signaling downstream of Dachsous through analysis of its intracellular domain.

Hormonal influence on maize inflorescence development and reproduction.

Different plant hormones contribute to maize reproductive success. Maize is a major crop species and significantly contributes directly and indirectly to human calorie uptake. Its success can be mainly attributed to its unisexual inflorescences, the tassel and the ear, whose formation is regulated by complex genetic and hormonal networks, and is influenced by environmental cues such as temperature, and nutrient and water availability.

Translation profiling of stress-induced small proteins reveals a novel link among signaling systems.

Signaling networks allow adaptation to stressful environments by activating genes that counteract stressors. Small proteins (≤ 50 amino acids long) are a rising class of stress response regulators. encodes over 150 small proteins, most of which lack phenotypes and their biological roles remain elusive.

Diversification and conservation of DNA binding specificities of SPL family of transcription factors.

SQUAMOSA Promoter-Binding Protein-Like (SPL) transcription factors play vital roles in plant development and stress responses. In this study, we report a comprehensive DNA Affinity Purification sequencing (DAP-seq) analysis for 14 of the 16 SPL transcription factors in , providing valuable insights into their DNA-binding specificities. We performed Gene Ontology (GO) analysis of the target genes to reveal their convergent and diverse biological functions among SPL family proteins.

New Viruses Infecting Hyperthermophilic Bacterium .

Highly diverse phages infecting thermophilic bacteria of the genus have been isolated over the years from hot springs around the world. Many of these phages are unique, rely on highly unusual developmental strategies, and encode novel enzymes. The variety of phages is clearly undersampled, as evidenced, for example, by a paucity of phage-matching spacers in CRISPR arrays.

Structural basis of archaeal FttA-dependent transcription termination.

The ribonuclease FttA (also known as aCPSF and aCPSF1) mediates factor-dependent transcription termination in archaea. Here we report the structure of a Thermococcus kodakarensis transcription pre-termination complex comprising FttA, Spt4, Spt5 and a transcription elongation complex (TEC). The structure shows that FttA interacts with the TEC in a manner that enables RNA to proceed directly from the TEC RNA-exit channel to the FttA catalytic centre and that enables endonucleolytic cleavage of RNA by FttA, followed by 5'→3' exonucleolytic cleavage of RNA by FttA and concomitant 5'→3' translocation of FttA on RNA, to apply mechanical force to the TEC and trigger termination.

Transcriptional corepressors in maize maintain meristem development.

The formation of the plant body proceeds in a sequential postembryonic manner through the action of meristems. Tightly coordinated meristem regulation is required for development and reproductive success, eventually determining yield in crop species. In maize (Zea mays), the RAMOSA1 ENHANCER LOCUS2 (REL2) family of transcriptional corepressors includes four members, REL2, RELK1 (REL2-LIKE1), RELK2, and RELK3.

Structural basis of RfaH-mediated transcription-translation coupling.

The NusG paralog RfaH mediates bacterial transcription-translation coupling in genes that contain a DNA sequence element, termed an ops site, required for pausing RNA polymerase (RNAP) and for loading RfaH onto the paused RNAP. Here, we report cryo-electron microscopy structures of transcription-translation complexes (TTCs) containing Escherichia coli RfaH. The results show that RfaH bridges RNAP and the ribosome, with the RfaH N-terminal domain interacting with RNAP and the RfaH C-terminal domain interacting with the ribosome.

A virally encoded tRNA neutralizes the PARIS antiviral defence system.

Viruses compete with each other for limited cellular resources, and some deliver defence mechanisms that protect the host from competing genetic parasites. The phage antirestriction induced system (PARIS) is a defence system, often encoded in viral genomes, that is composed of a 55 kDa ABC ATPase (AriA) and a 35 kDa TOPRIM nuclease (AriB). However, the mechanism by which AriA and AriB function in phage defence is unknown.

Posttranscriptional tuning of gene expression over a large dynamic range in synthetic tobacco chloroplast operons.

Achieving optimally balanced gene expression within synthetic operons requires regulatory elements capable of providing a spectrum of expression levels. In this study, we investigate the expression of gfp reporter gene in tobacco chloroplasts, guided by variants of the plastid atpH 5' UTR, which harbors a binding site for PPR10, a protein that activates atpH at the posttranscriptional level. Our findings reveal that endogenous tobacco PPR10 confers distinct levels of reporter activation when coupled with the tobacco and maize atpH 5' UTRs in different design contexts.

Closed floral structure for self-pollination in cultivated tomato.

Cultivated tomatoes exhibit cleistogamy - self-pollination within closed flowers. Wu et al. report that three HD-Zip IV genes and Style2.

Genome-wide analysis of Smad and Schnurri transcription factors in demonstrates widespread interaction and a function in collagen secretion.

Smads and their transcription factor partners mediate the transcriptional responses of target cells to secreted ligands of the Transforming Growth Factor-β (TGF-β) family, including those of the conserved bone morphogenetic protein (BMP) family, yet only a small number of direct target genes have been well characterized. In the BMP2/4 ortholog DBL-1 regulates multiple biological functions, including body size, via a canonical receptor-Smad signaling cascade. Here, we identify functional binding sites for SMA-3/Smad and its transcriptional partner SMA-9/Schnurri based on ChIP-seq peaks (identified by modEncode) and expression differences of nearby genes identified from RNA-seq analysis of corresponding mutants.

Transcription factor binding site divergence across maize inbred lines drives transcriptional and phenotypic variation.

Regulatory elements are important constituents of plant genomes that have shaped ancient and modern crops. Their identification, function, and diversity in crop genomes however are poorly characterized, thus limiting our ability to harness their power for further agricultural advances using induced or natural variation. Here, we use DNA affinity purification-sequencing (DAP-seq) to map transcription factor (TF) binding events for 200 maize TFs belonging to 30 distinct families and heterodimer pairs in two distinct inbred lines historically used for maize hybrid plant production, providing empirical binding site annotation for 5.