The immune signaling pathways of Manduca sexta

Abstract

Signal transduction pathways and their coordination are critically important for proper functioning of animal immune systems. Our knowledge of the constituents of the intracellular signaling network in insects mainly comes from genetic analyses in Drosophila melanogaster. To facilitate future studies of similar systems in the tobacco hornworm and other lepidopteran insects, we have identified and examined the homologous genes in the genome of Manduca sexta. Based on 1:1 orthologous relationships in most cases, we hypothesize that the Toll, Imd, MAPK-JNK-p38 and JAK-STAT pathways are intact and operative in this species, as are most of the regulatory mechanisms. Similarly, cellular processes such as autophagy, apoptosis and RNA interference probably function in similar ways, because their mediators and modulators are mostly conserved in this lepidopteran species. We have annotated a total of 186 genes encoding 199 proteins, studied their domain structures and evolution, and examined their mRNA levels in tissues at different life stages. Such information provides a genomic perspective of the intricate signaling system in a non-drosophiline insect.

Toll ligand Spätzle3 controls melanization in the stripe pattern formation in caterpillars

“…Because Spz proteins should be processed before activation, this result may be caused by the inefficient processing of ectopically expressed Spz-3. To validate this possibility, we next made constructs of processed Spz-3, which included only the CK domain and digested just after Arg-His-Ala-Arg (RHAR) sequence (25) (Fig. 3A, red triangle).…”

“…This result indicates that the full-length constructs of Spz-3 could not be processed appropriately under the experimental conditions. A recent report on M. sexta surmised that Spz-3 processing is mediated by furin-like enzymes based on the recognition sequence RHAR (25). Thus, the full-length construct integrated by somatic transgenesis into the random site of the host genome may not be expressed appropriately when the furin-like processing enzyme is expressed.…”

Reconfiguration of the immune system network during food limitation in the caterpillarManduca sexta

“…A similar issue exists with respect to changes in immune gene expression, as many more genes are involved in immunity than were measured in this study (e.g. see He et al, 2015;Cao et al, 2015). Additionally, recent studies show that genes and molecules not traditionally considered 'immune genes' are also important for the immune response (Adamo et al, 2008;Unckless et al, 2015) and a wider view is needed to develop a comprehensive understanding of the immune system network.…”

“…1, see Jiang, 2008;Kanost and Gorman, 2008;Christen et al, 2012;Zhang et al, 2011;Cao et al, 2015;Chevignon et al, 2015). This assessment included different aspects of constitutive immunity, i.e.…”

Changes in the Plasma Proteome of Manduca sexta Larvae in Relation to the Transcriptome Variations after an Immune Challenge: Evidence for High Molecular Weight Immune Complex Formation

“…In contrast, a few intracellular, immunity-related proteins were detected in the plasma samples (Table S2). Our previous studies on M. sexta immune signal transducers showed their gene expression changed less dramatically after the challenge (9,22). The weak correlation is largely covered by the noises of other proteins (e.g.…”