Codon Optimization-based Whole-gene Scanning Identifies Hidden Nucleotides Essential for Bombyx mori Nucleopolyhedrovirus polyhedrin Hyperexpression.

During the late stage of infection, alphabaculoviruses produce many occlusion bodies (OBs) in the nuclei of the insect host's cells through the hyperexpression of polyhedrin (POLH), a major OB component encoded by polh. The strong polh promoter has been used to develop a baculovirus expression vector system for recombinant protein expression in cultured insect cells and larvae. However, the relationship between POLH accumulation and the polh coding sequence remains largely unelucidated.

Expression of the Wolbachia male-killing factor Oscar impairs dosage compensation in lepidopteran embryos.

Wolbachia are intracellular bacteria in insects that can manipulate the sexual development and reproduction by male killing or other methods. We have recently identified a Wolbachia protein named Oscar that acts as a male-killing factor for lepidopteran insects. Oscar interacts with the Masculinizer (Masc) protein, which is required for both masculinization and dosage compensation (DC) in lepidopteran insects.

A seamless connection from the burst sequence to the start codon is essential for polyhedrin hyperexpression in alphabaculoviruses.

Alphabaculoviruses produce a large number of occlusion bodies (OBs) in host cells during the late stage of infection. OBs are mainly composed of polyhedrin (POLH), and high-level transcription of the polh gene has been exploited to express foreign proteins in insect cells. While making Bombyx mori nucleopolyhedrovirus (BmNPV) polh mutants using a conventional transfer vector-based method, we noticed that a virus with a short sequence insertion just before the polh start codon produces fewer very small OBs.

A Wolbachia factor for male killing in lepidopteran insects.

Bacterial symbionts, such as Wolbachia species, can manipulate the sexual development and reproduction of their insect hosts. For example, Wolbachia infection induces male-specific death in the Asian corn borer Ostrinia furnacalis by targeting the host factor Masculinizer (Masc), an essential protein for masculinization and dosage compensation in lepidopteran insects. Here we identify a Wolbachia protein, designated Oscar, which interacts with Masc via its ankyrin repeats.

Characterization of nuclear localization signal in Ostrinia furnacalis Masculinizer protein.

Bombyx mori Masculinizer protein (BmMasc) is essential for both masculinization and dosage compensation in B. mori. We previously identified a bipartite nuclear localization signal (NLS) of BmMasc and two essential residues (lysine at 274 [K274] and arginine at 275 [R275]) implicated in its function.

Characterization of Bombyx mori nucleopolyhedrovirus infection in fat body-derived Bombyx mori cultured cells.

Bombyx mori nucleopolyhedrovirus (BmNPV) is known to replicate in many tissues of Bombyx mori larvae. However, the cell lines used for BmNPV research are predominantly derived from B. mori ovaries or early embryos.

Bombyx mori nucleopolyhedrovirus Bm96 suppresses viral virulence in Bombyx mori larvae.

Bombyx mori nucleopolyhedrovirus (BmNPV) is a severe pathogen for the domestic silkworm, Bombyx mori. BmNPV harbors over 140 protein-coding genes in its 128.4 kilobase pair-long double-stranded genome.

Identification of reference genes for quantitative expression analysis using large-scale RNA-seq data of Arabidopsis thaliana and model crop plants.

In quantitative gene expression analysis, normalization using a reference gene as an internal control is frequently performed for appropriate interpretation of the results. Efforts have been devoted to exploring superior novel reference genes using microarray transcriptomic data and to evaluating commonly used reference genes by targeting analysis. However, because the number of specifically detectable genes is totally dependent on probe design in the microarray analysis, exploration using microarray data may miss some of the best choices for the reference genes.

Identification and characterization of host factors interacting with Bombyx mori nucleopolyhedrovirus ORF8.

The orf8 gene (Bm8) in Bombyx mori nucleopolyhedrovirus (BmNPV) is one of 17 genes unique to group I NPVs and is expressed as an early gene. We have reported that Bm8 may play an important role during viral infection and that Bm8 protein co-localized with IE1 to specific nuclear foci throughout infection. It was also demonstrated that both IE1 and BmNPV hr facilitate this localization of Bm8.

Baculovirus-encoded protein BV/ODV-E26 determines tissue tropism and virulence in lepidopteran insects.

Lepidopteran nucleopolyhedroviruses (NPVs) show distinct tissue tropism in host insect larvae. However, the molecular mechanism of this tropism is largely unknown. We quantitatively investigated NPV tissue tropism by measuring mRNA levels of viral genes in 16 tissues from Bombyx mori NPV (BmNPV)-infected B.

Role of the ubiquitin-proteasome system in Bombyx mori nucleopolyhedrovirus infection.

The ubiquitin-proteasome system plays a central role in the degradation of intracellular proteins and is often required for efficient virus infection. Homologues of ubiquitin are found in all group I nucleopolyhedroviruses (NPVs), but their roles in NPV infection are still unclear. This study found that the specific proteasome inhibitor MG-132 markedly reduced budded virus (BV) production and polyhedrin expression in Bombyx mori NPV (BmNPV)-infected BmN-4 cells.