Karyopherins, including alpha and beta types, are transport proteins in the eukaryotic cell that carry cargoes across nuclear pore complexes into or out of the nucleus. In this study, full open reading frames of one beta and three alpha types of karyopherin were cloned from cDNA of the domestic silkworm (Bombyx mori). The one beta and three alpha types’ open reading frames were 2661, 1563, 1515, and 1551 base pairs long, respectively, and coded 886, 520, 504, and 516 amino acids, respectively.
In the silkworm (Bombyx mori), tolerance to fluoride and scaleless wings are controlled by the dominant gene Dtf (dominant tolerance to fluoride) and recessive gene nlw (no Lepidoptera wings), respectively, and these genes have been mapped by using simple sequence repeat and sequence tag site markers. Marker-assisted evaluation and selection of silkworms with fluoride tolerance and scaleless wings were used for predicting fluoride resistance and scaleless wings in backcrossed animals.
Fatty acid desaturases exist in all living organisms and play important roles in many different biologic processes, such as fatty acid metabolism, lipid biosynthetic processes, and pheromone biosynthetic processes. Using the available silkworm genome sequence, we identified 14 candidate fatty acid desaturase genes. Eleven genes contain 3 conserved histidine cluster motifs and 4 transmembrane domains, but their N-terminal residues exhibit obvious diversity.
Bombyx mori BmHRP28 and BmPSI, which belong to the family of RNA-binding proteins, have been identified binding to the female-specific exon 4 of the sex-determining gene Bmdsx pre-mRNA. However, the relationships between BmHRP28 and BmPSI still remain unclear. In this study, we carried out yeast two-hybrid (Y2H) and co-immunoprecipitation (Co-IP) analyses to address them. Y2H analysis showed that there was little or no direct binding between the BmHRP28 and BmPSI proteins.
In the silkworm (Bombyx mori), resistance to the Zhenjiang (China) strain of the densonucleosis virus (DNV-Z) is controlled by the recessive gene nsd-Z (non-susceptible to DNV-Z), which is linked to 7 simple-sequence repeat markers. Marker-assisted evaluation and selection of DNV-Z-resistant silkworms were used for predicting DNV-resistance in backcrossed animals. A silkworm race was bred using this method, and its economic characteristics were found to be similar to those of commercial silkworm races.
The quantitative trait loci (QTLs) associated with cocoon traits in silkworms were mapped in 44 individuals of a backcross of Dazao females with hybrid F1 males; the hybrid males were from females of inbred C100 strain, which have white cocoons and superior cocoon traits, crossed with males of inbred strain Dazao, which have green cocoons and inferior cocoon traits.
Previous reports demonstrated that actin is necessary for nucleocapsid transport and viral gene expression during nucleopolyhedrovirus infection of Bombyx mori. The first intron of B. mori A3 actin contains a cryptic promoter that drives expression of a rare isoform. We detected differences in the size and nucleotide composition of the first intron of the A3 actin gene from B. mori strain C24A, which is more resistant to nucleopolyhedrovirus than the M11A strain (22 and 95% lethality, respectively).
Conformation-sensitive gel electrophoresis is a useful method for identifying allele polymorphism; it provides co-dominant molecular markers. Using this method, we identified genetic variability in the third intron of the fibroin light chain gene, fib-L, in six Bombyx mori strains. Only Chinese C21A strain did not demonstrate allelic alterations, showing only homoduplex DNA molecules. We found distinct heteroduplex profiles in the Japanese HAA, M12B and M19-2 and the Chinese C25B and C24-2 strains.
A multiple nucleopolyhedrovirus previously isolated from infected Bombyx mori L. larvae (BmMNPV) in Paraná state, Brazil, was inoculated into B. mori larvae to examine susceptibility and cytopathology in silk gland cells. The anterior, middle and posterior silk glands were removed from the infected silkworm at different times post-inoculation and processed for cytopathology studies by light and transmission electron microscopy. BmMNPV infection was only detected at 72 h post-inoculation in cells of the middle and posterior silk glands.