Genetic interactions between the DBL-1/BMP-like pathway anddpybody size–associated genes inCaenorhabditis elegans

Abstract

How BMP signaling and other body size regulators interact is not clear. We found interactions between Caenorhabditis elegans DBL-1/BMP and ECM, proteins that may modify or secrete DBL-1, and the SET domain protein BLMP-1. DBL-1 signaling may control downstream targets, some through BLMP-1, that affect size either directly or by feeding back on DBL-1 signaling.

Caenorhabditis elegans saposin-like spp-9 is involved in specific innate immune responses

“…In three independent trials, the dbl-1(-); spp-9p::gfp animals when fed on standard lab food, E. coli strain OP50, showed a significantly increased fluorescence, consistent with previous reports (Fig. 4a, e) [21,30]. We observed that animals lacking dbl-1 when fed on S. epidermidis, E. cloacae, and S. marcescens showed a further increase in fluorescence in comparison to the control (dbl-1(-); spp-9p::gfp animals fed on E. coli OP50) ( Fig.…”

“…S2b). These qRT-PCR results support previously reported microarray results and the use of spp-9p::GFP as a reporter for DBL-1 pathway signaling [21,30]. spp-9 expression depends on DBL-1 and other innate immune response signaling pathways, depending on pathogen DBL-1 signaling pathway regulates expression of many innate immunity genes and is also involved in mounting protective immune responses against pathogens [13,18,[44][45][46][47][48].…”

“…Animals can mount responses to a variety of environmental stresses. Loss of some dpy genes that encode cuticle collagens induce glycerol, osmotic, and detoxification responses, but do not change spp-9 reporter expression [30,[38][39][40][41]. Starvation is another stress, and spp-3 expression is induced in starved animals [24,25].…”

“…Studies by our lab and others have shown that the activity of spp-9 is highly regulated by DBL-1 in an inverse fashion. Animals overexpressing DBL-1 show reduced spp-9p::GFP activity and animals lacking DBL-1 display high reporter activity [21,30]. We tested if DBL-1 regulates endogenous levels of spp-9 expression by quantitative real-time PCR, comparing spp-9 expression levels from dbl-1 mutants to the wild-type control.…”

“…spp-9 expression is upregulated in response to loss of DKF-2/protein kinase D [29]. spp-9 is also negatively regulated by the DBL-1 signaling pathway and is used as DBL-1 pathway reporter [21,30]. While spp-9 has been shown to be a DBL-1-responsive gene, here we characterized the role of spp-9 in the larger context of starvation stress and innate immunity.…”