ecdysterone and Gram-Positive-Bacterial-Infections

Programmed cell death 2 (PDCD2) is a highly conserved eukaryotic protein indispensable for various physiological processes such as cell proliferation, development, and apoptosis. In the present study, we identified a Zinc finger protein RP-8 from the silkworm, Bombyx mori (BmZfrp8), the ortholog of PDCD2 protein. The quantitative real-time PCR analysis revealed the ubiquitous distribution of BmZfrp8 in the different tissues; however, the gene's transcription level was highest in those of the silk gland, testis, and ovary. Additionally, the expression levels of BmZfrp8 were unequal on different days of embryonic development, and it reached the highest level on the 5th day of early development. The challenge with pathogens influenced the expression level of BmZfrp8 in both hemocyte and fat body when compared with the control. Administration of 20-hydroxyecdysone significantly enhanced the BmZfrp8 expression in hemocyte. The knock-down of BmZfrp8 by double-stranded RNA suppressed the expression of developmental pathway associated genes as well as cell cycle-associated genes. Furthermore, the RNAi treated cells also showed cell cycle arrest compared to the control group. Taken together, BmZfrp8 may have a critical biological role in of B. mori, since it regulates the expression of the developmental pathway and cell cycle-associated genes.

Topics: Animals; Apoptosis Regulatory Proteins; Bacillus subtilis; Bombyx; Cell Cycle; Cell Proliferation; Ecdysterone; Gene Expression Regulation, Developmental; Gene Knockdown Techniques; Gram-Positive Bacterial Infections; Hemocytes; Humans; Insect Proteins; Transcriptome

Clip-domain serine proteases (CLIPs), characterized by regulatory module clip domains, constitute an important serine protease family identified in insects and other arthropods. They participate in host immune response and embryonic development in a cascade-activated manner. Here, we present a genome-wide identification and expression analysis of CLIP genes in the silkworm, Bombyx mori. A total of 26 CLIP genes were identified in the silkworm genome. Bioinformatics analysis indicated that these CLIPs clustered into four subfamilies (CLIPA-D), and exhibit a close evolutionary relationship with CLIPs of Manduca sexta. Tissue expression profiling revealed that silkworm CLIP genes are mainly expressed in the integument, head, fat body, and hemocytes. Temporal expression profiles showed that 15 CLIP genes were predominantly expressed during the fifth-instar larval stage, early and later period of the pupal stage, and adult stage, whereas 10 CLIP genes were mainly expressed in the wandering stage and middle to later period of the pupal stage in the integument. Pathogens and 20-hydroxyecdysone (20E) induction analysis indicated that 14 CLIP genes were positively regulated by 20E, 9 were negatively regulated by 20E but positively regulated by pathogens, and 5 were positively regulated by both factors in the integument. Together, these results suggested that silkworm CLIP genes may play multiple functions in integument development, including melanization of new cuticle, molting and immune defense. Our data provide a comprehensive understanding of CLIP genes in the silkworm integument and lays a foundation for further functional studies of CLIP genes in the silkworm.

Topics: Animals; Arthropod Proteins; Bombyx; Cells, Cultured; Ecdysterone; Escherichia coli; Escherichia coli Infections; Gene Expression Profiling; Gene Expression Regulation; Gram-Positive Bacterial Infections; Immunity; Micrococcus luteus; Organ Specificity; Protein Domains; Serine Proteases