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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Parasitic Diseases Laboratory » Research » Publications at this Location » Publication #287064
Title: Neospora caninum dynein LC8 light chain 2 is identical to that of Toxoplasma gondii and differentially produced by pathogenically distinct isolates

Author
item CAO, LILI - Jilin University
item QU, GUANGGANG - Shandong Academy Of Agricultural Sciences
item Fetterer, Raymond
item ZHANG, XICHEN - Jilin University
item Tuo, Wenbin

Submitted to: Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2018
Publication Date: 4/1/2019
Citation: Cao, L., Qu, G., Fetterer, R.H., Zhang, X., Tuo, W. 2019. Neospora caninum dynein LC8 light chain 2 is identical to that of Toxoplasma gondii and differentially produced by pathogenically distinct isolates. Parasitology. https://doi.org/10.1017/S003118201800207X.
DOI: https://doi.org/10.1017/S003118201800207X

Interpretive Summary: Neospora caninum is a parasite causing abortion in cattle. A N.caninum cytoplasmic dynein LC8 light chain (NcDYNLL) as an immune modulator was characterized. Our previous studies indicated that NcDYNLL production was suppressed in a non-pathogenic clone of N. caninum, suggesting that this protein is important for parasite virulence. We have showed that the NcDYNLL identified in the present study is type 2, and thus named NcDYNLL2. NcDYNLL2 was cloned and expressed in Escherichia coli and the recombinant NcDYNLL2 was purified. As expected, NcDYNLL2 was lower in the non-pathogenic isolate than in the wild type isolate. NcDYNLL2 was released by the tachyzoites at low levels, but the release was increased when tachyzoites were treated with either calcium ionophore or ethanol. The data suggest that NcDYNLL2 is actively secreted and its secretion is regulated in a similar mechanism for the microneme proteins. NcDYNLL2 was primarily localized to the apical end of the parasite. Furthermore, recombinant NcDYNLL2 induced production of host immune mediators. Taken together, these results suggest that NcDYNLL2 is a secretory protein which may cross-regulate host immunity against the parasite. This research will facilitate the understanding of parasite-host relationship and will advance the process of development of a vaccine against neosporosis. This research will benefit the cattle industry and the research community.

Technical Abstract: Cytoplasmic dyneins, including the dynein LC8 light chains (DYNLL), belong to the microtubule minus-end-directed motor proteins and are involved in many cellular processes. A Neospora caninum cytoplasmic dynein LC8 light chain (NcDYNLL) was characterized in this study. Previous microarray studies revealed that NcDYNLL was down-regulated in the non-pathogenic clone Ncts-8 when compared to the wild type NC1 isolate. The present study showed that DYNLLs from different species are highly conserved (>85% homology), and the NcDYNLL belongs to the DYNLL2 family. NcDYNLL2 and Toxoplasma gondii DYNLL2 have identical amino acid sequences, although they are slightly divergent (89% similar) at the genetic level. NcDYNLL2 was cloned and expressed in Escherichia coli and the recombinant NcDYNLL2 was purified. NcDYNLL2 was present in soluble and insoluble fractions of tachyzoite lysate prepared by sonication. As expected, NcDYNLL2 was lower (P<0.05) in the Ncts-8 when compared to that of NC1 isolate. NcDYNLL2 was released by the tachyzoites at low levels, however, the release was increased (P<0.05) when tachyzoites were treated with either 5uM calcium ionophore or 1% ethanol. The data suggest that NcDYNLL2 may be actively secreted and its release regulated in a similar mechanism for the microneme proteins. NcDYNLL2 had a diffuse distribution pattern with a relatively more intense accumulation towards the apical end. Furthermore, rNcDYNLL2 induced tumor necrosis factor-alpha (TNF-alpha' and interleukin-12 (IL-12) production by murine bone marrow-derived dendritic cells. Taken together, these results suggest that NcDYNLL2 is a secretory protein which may be associated with virulence and cross-regulate host immunity.