Computational analysis of target genes in monkeypox virus infection and potential therapeutic precursors.

BACKGROUND: Monkeypox is an orthopoxvirus that is responsible for zoonotic infections in humans. The virus has recently spread rapidly and the WHO has listed it as an international public health emergency of concern. RESEARCH DESIGN AND METHODS: Here, we used network analysis and gene enrichment protocols and analyzed datasets of MPXV infection that induced host cell gene expression list and subsequently mapped them against two herbal target gene lists which highlighted considerable coherence in pharmacological attributes with COVID-19. Molecular docking and simulation were performed for the screened compounds. RESULTS: Our results identified ß-carotene and kaempferol possessing tremendous ability against the MPXV PLD protein. Both compounds were subjected to each of 100 ns molecular dynamics simulation and were found native to the PLD pocket. MM-PB (GB) SA analyses indicated -25.4, -40.1 kcal/mol and -17.2, -26.4kcal/mol of ΔGbind to the active pocket of PLD. Our data suggest the adaptive nature of the MPXV PLD active pocket toward hydrophobic inhibitors. CONCLUSION: These results will be of high importance for the viral researchers to be tested in wet lab settings in designing potential inhibitors.

Antagonistic relationship of NuA4 with the non-homologous end-joining machinery at DNA damage sites.

The NuA4 histone acetyltransferase complex, apart from its known role in gene regulation, has also been directly implicated in the repair of DNA double-strand breaks (DSBs), favoring homologous recombination (HR) in S/G2 during the cell cycle. Here, we investigate the antagonistic relationship of NuA4 with non-homologous end joining (NHEJ) factors. We show that budding yeast Rad9, the 53BP1 ortholog, can inhibit NuA4 acetyltransferase activity when bound to chromatin in vitro. While we previously reported that NuA4 is recruited at DSBs during the S/G2 phase, we can also detect its recruitment in G1 when genes for Rad9 and NHEJ factors Yku80 and Nej1 are mutated. This is accompanied with the binding of single-strand DNA binding protein RPA and Rad52, indicating DNA end resection in G1 as well as recruitment of the HR machinery. This NuA4 recruitment to DSBs in G1 depends on Mre11-Rad50-Xrs2 (MRX) and Lcd1/Ddc2 and is linked to the hyper-resection phenotype of NHEJ mutants. It also implicates NuA4 in the resection-based single-strand annealing (SSA) repair pathway along Rad52. Interestingly, we identified two novel non-histone acetylation targets of NuA4, Nej1 and Yku80. Acetyl-mimicking mutant of Nej1 inhibits repair of DNA breaks by NHEJ, decreases its interaction with other core NHEJ factors such as Yku80 and Lif1 and favors end resection. Altogether, these results establish a strong reciprocal antagonistic regulatory function of NuA4 and NHEJ factors in repair pathway choice and suggests a role of NuA4 in alternative repair mechanisms in situations where some DNA-end resection can occur in G1.

DNA Damage-Induced Phosphorylation of Histone H2A at Serine 15 Is Linked to DNA End Resection.

The repair of DNA double-strand breaks (DSBs) occurs in chromatin, and several histone posttranslational modifications have been implicated in the process. Modifications of the histone H2A N-terminal tail have also been linked to DNA damage response, through acetylation or ubiquitination of lysine residues that regulate repair pathway choice. Here, we characterize a new DNA damage-induced phosphorylation on chromatin, at serine 15 of H2A in yeast. We show that this SQ motif functions independently of the classical S129 C-terminal site (γ-H2A) and that mutant-mimicking constitutive phosphorylation increases cell sensitivity to DNA damage. H2AS129ph is induced by Tel1ATM and Mec1ATR, and the loss of Lcd1ATRIP or Mec1 signaling decreases γ-H2A spreading distal to the DSB. In contrast, H2AS15ph is completely dependent on Lcd1ATRIP, indicating that this modification only happens when end resection is engaged. This is supported by an increase in replication protein A (RPA) and a decrease in DNA signal near the DSB in H2A-S15E phosphomimic mutants, indicating higher resection. In mammals, this serine is replaced by a lysine (H2AK15) which undergoes an acetyl-monoubiquityl switch to regulate binding of 53BP1 and resection. This regulation seems functionally conserved with budding yeast H2AS15 and 53BP1-homolog Rad9, using different posttranslational modifications between organisms but achieving the same function.

Synthesis and characterization of manganese ferrite from low grade manganese ore through solid state reaction route.

Manganese ferrite spinel has been synthesized by using low grade manganese ore and ferric oxide as sources of manganese oxide and iron oxide through solid state reaction route by taking manganese and iron mole ratio of 1:2 respectively. The impact of sintering temperature on phase composition and particle size is investigated. Similarly, the impact of frequency on dielectric constant, dielectric loss, AC (alternating current) conductivity and tangent losses is also investigated. The results shows the presence of spinel structure manganese ferrite (MnFe2O4) as the major phase for the sample sintered at 1200 °C. It has been established that the crystallite size increase with rise in sintering temperature. The surface morphology of the sample sintered at 1200 °C show pyramidal and triangular shape grains. The dielectric constant (ε') and dielectric losses (ε'') were observed to decrease with increasing the sintering temperature and frequency. Furthermore, the AC (alternating current) conductivity was found to rise with rise in applied frequency. On the other hand, the tangent losses falls considerably with rise in applied frequency.

Architecture of the Saccharomyces cerevisiae NuA4/TIP60 complex.

The NuA4/TIP60 acetyltransferase complex is required for gene regulation, DNA repair and cell cycle progression. The limited structural information impeded understanding of NuA4/TIP60 assembly and regulatory mechanism. Here, we report the 4.7 Å cryo-electron microscopy (cryo-EM) structure of a NuA4/TIP60 TEEAA assembly (Tra1, Eaf1, Eaf5, actin and Arp4) and the 7.6 Å cryo-EM structure of a TEEAA-piccolo assembly (Esa1, Epl1, Yng2 and Eaf6). The Tra1 and Eaf1 constitute the assembly scaffold. The Eaf1 SANT domain tightly binds to the LBE and FATC domains of Tra1 by ionic interactions. The actin/Arp4 peripherally associates with Eaf1 HSA domain. The Eaf5/7/3 (TINTIN) and piccolo modules largely pack against the FAT and HEAT repeats of Tra1 and their association depends on Eaf1 N-terminal and HSA regions, respectively. These structures elucidate the detailed architecture and molecular interactions between NuA4 subunits and offer exciting insights into the scaffolding and regulatory mechanisms of Tra1 pseudokinase.

Molecular Architecture of the Essential Yeast Histone Acetyltransferase Complex NuA4 Redefines Its Multimodularity.

Conserved from yeast to humans, the NuA4 histone acetyltransferase is a large multisubunit complex essential for cell viability through the regulation of gene expression, genome maintenance, metabolism, and cell fate during development and stress. How the different NuA4 subunits work in concert with one another to perform these diverse functions remains unclear, and addressing this central question requires a comprehensive understanding of NuA4's molecular architecture and subunit organization. We have determined the structure of fully assembled native yeast NuA4 by single-particle electron microscopy. Our data revealed that NuA4 adopts a trilobal overall architecture, with each of the three lobes constituted by one or two functional modules. By performing cross-linking coupled to mass spectrometry analysis and in vitro protein interaction studies, we further mapped novel intermolecular interfaces within NuA4. Finally, we combined these new data with other known structural information of NuA4 subunits and subassemblies to construct a multiscale model to illustrate how the different NuA4 subunits and modules are spatially arranged. This model shows that the multiple chromatin reader domains are clustered together around the catalytic core, suggesting that NuA4's multimodular architecture enables it to engage in multivalent interactions with its nucleosome substrate.

Yaf9 subunit of the NuA4 and SWR1 complexes targets histone H3K27ac through its YEATS domain.

Yaf9 is an integral part of the NuA4 acetyltransferase and the SWR1 chromatin remodeling complexes. Here, we show that Yaf9 associates with acetylated histone H3 with high preference for H3K27ac. The crystal structure of the Yaf9 YEATS domain bound to the H3K27ac peptide reveals that the sequence C-terminal to K27ac stabilizes the complex. The side chain of K27ac inserts between two aromatic residues, mutation of which abrogates the interaction in vitro and leads in vivo to phenotypes similar to YAF9 deletion, including loss of SWR1-dependent incorporation of variant histone H2A.Z. Our findings reveal the molecular basis for the recognition of H3K27ac by a YEATS reader and underscore the importance of this interaction in mediating Yaf9 function within the NuA4 and SWR1 complexes.

TINTIN, at the interface of chromatin, transcription elongation, and mRNA processing.

Recent work including high-resolution genome-wide analysis uncovered a new trimeric complex involved in transcription elongation, both as an integral part of the NuA4 histone acetyltransferase and as an independent functional entity. The complex is conserved in eukaryotes and is named TINTIN, for Trimer Independent of NuA4 for transcription Interactions with Nucleosomes. This point of view covers the current knowledge regarding TINTIN's function in modulating chromatin structure and influencing transcription elongation in eukaryotes. It also points to several physical and functional links to co-transcriptional processes, including interactions with the mRNA splicing machinery and the nuclear exosome.

Draft Genome Sequence of Sphingobium chinhatense Strain IP26T, Isolated from a Hexachlorocyclohexane Dumpsite.

Sphingobium chinhatense strain IP26(T) is a conducive hexachlorocyclohexane (HCH) degrader isolated from a heavily contaminated (450 mg HCH/g soil) HCH dumpsite. IP26(T) degrades α-, ß-, γ-, and δ-HCH, which are highly persistent in the environment. Here we report the draft genome sequence (~5.8 Mbp) of this strain.