Dataset Information

A DAF-3 co-Smad molecule functions in Haemonchus contortus development.

ABSTRACT: BACKGROUND:The Smad proteins function in TGF-? signalling transduction. In the model nematode Caenorhabditis elegans, the co-Smad, DAF-3 mediates R-Smads and performs a central role in DAF-7 signal transduction, regulating dauer formation and reproductive processes. Considering the divergent evolutionary patterns of the DAF-7 signalling pathway in parasitic nematodes, it is meaningful to explore the structure and function of DAF-3 in parasitic nematodes, such as Haemonchus contortus. METHODS:A daf-3 gene (Hc-daf-3) and its predicted product (Hc-DAF-3) were identified from H. contortus and characterised using integrated genomic and genetic approaches. In addition to immunohistochemistry employed to localise Hc-DAF-3 within adult worm sections, real-time PCR was conducted to assess the transcriptional profiles in different developmental stages of H. contortus and RNA interference (RNAi) was performed in vitro to assess the functional importance of Hc-daf-3 in the development of H. contortus. RESULTS:Hc-DAF-3 sequences predicted from Hc-daf-3 displayed typical features of the co-Smad subfamily. The native Hc-DAF-3 was localised to the gonad and cuticle of adult parasites. In addition, Hc-daf-3 was transcribed in all developmental stages studied, with a higher level in the third-stage larvae (L3) and adult females. Moreover, silencing Hc-daf-3 by RNAi retarded L4 development. CONCLUSION:The findings of the present study demonstrated an important role of Hc-DAF-3 in the development of H. contortus larvae.

SUBMITTER: Di W

PROVIDER: S-EPMC6935219 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:BACKGROUND:Smad proteins are essential cellular mediators within the transforming growth factor-β (TGF-β) superfamily. They directly transmit incoming signals from the cell surface receptors to the nucleus. In spite of their functional importance, almost nothing is known about Smad proteins in parasitic nematodes including Haemonchus contortus, an important blood-sucking nematode of small ruminants. METHODS:Based on genomic and transcriptome data for H. contortus and using bioinformatics methods, a Smad homologue (called Hco-daf-8) was inferred from H. contortus and the structural characteristics of this gene and its encoded protein Hco-DAF-8 established. Using real-time PCR and immunofluorescence assays, temporal transcriptional and spatial expression profiles of Hco-daf-8 were studied. Gene rescue in Caenorhabditis elegans was then applied to assess the function of Hco-daf-8 and a specific inhibitor of human Smad3 (called SIS3) was employed to evaluate the roles of Hco-DAF-8 in H. contortus development. RESULTS:The features of Hco-DAF-8 (502 amino acids), including conserved R-Smad domains and residues of the L3-loop that determine pathway specificity, are consistent with a TGF-β type I receptor-activated R-Smad. The Hco-daf-8 gene was transcribed in all developmental stages of H. contortus studied, with a higher level of transcription in the fourth-stage larval (L4) females and the highest level in adult males. Hco-DAF-8 was expressed in the platymyarian muscular cells, intestine and reproductive system of adult stages. Gene rescue experiments showed that Hco-daf-8 was able to partially rescue gene function in a daf-8 deficient mutant strain of C. elegans, leading to a resumption of normal development. In H. contortus, SIS3 was shown to affect H. contortus development from the exsheathed third-stage larvae (L3s) to L4s in vitro. CONCLUSIONS:These findings suggest that Hco-DAF-8, encoded by the gene Hco-daf-8, is an important cellular mediator of H. contortus development via the TGF-β signalling pathway. They provide a basis for future explorations of Hco-DAF-8 and associated pathways in H. contortus and other important parasitic nematodes.

Dataset Information

A DAF-3 co-Smad molecule functions in Haemonchus contortus development.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets