Differential expression of calcium-dependent protein kinase 4, tubulin tyrosine ligase, and methyltransferase by xanthurenic acid-induced Babesia bovis sexual stages

Authors: HUSSEIN, HALA - Washington State University; Johnson, Wendell; Taus, Naomi; CAPELLI-PEIXOTO, JANAINA - Washington State University; Suarez, Carlos; Mousel, Michelle; Ueti, Massaro

Submitted to: Parasites & Vectors
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/28/2021
Publication Date: 8/10/2021
Publication URL: https://handle.nal.usda.gov/10113/7470100
Citation: Hussein, H.E., Johnson, W.C., Taus, N.S., Capelli-Peixoto, J., Suarez, C.E., Mousel, M.R., Ueti, M.W. 2021. Differential expression of calcium-dependent protein kinase 4, tubulin tyrosine ligase, and methyltransferase by xanthurenic acid-induced Babesia bovis sexual stages. Parasites & Vectors. 14. Article 395. https://doi.org/10.1186/s13071-021-04902-3.
DOI: https://doi.org/10.1186/s13071-021-04902-3

Interpretive Summary: In this study we describe the identification of B. bovis genes associated with sexual development. Quantitative PCR (qPCR) analyses showed that these genes were expressed in in vitro induced sexual stages and tick specific stages during parasite development in tick midgut. We found that these genes are conserved among apicomplexan parasites, including the human parasite, Plasmodium falciparum. In addition, the data showed that xanthurenic acid is strongly involved in B. bovis sexual stage formation, in conclusion, these B. bovis genes are predicted to play a vital role in sexual reproduction, and parasite transmission. Our findings will be useful for a better understanding of B. bovis biology, especially sexual stage development. Understanding the biology of the parasite will help to develop an effective method of controlling bovine babesiosis.

Technical Abstract: Background: Babesia bovis is one of the most significant tick transmitted pathogens of cattle worldwide. Babesia bovis parasites have a complex lifecycle including development within the mammalian host and tick vector. Each life stage has multiple developmental forms that differ in morphology and metabolism. Differentiation between these forms is highly regulated in response to changes in the parasite’s environment. Understanding the mechanism by which these parasites respond to environmental changes and the transmission cycle through the biological vector is critically important for the development of bovine babesiosis control strategies. Results: In this study we describe the identification of B. bovis genes associated with sexual development, calcium-dependent protein kinase 4 (cdpk4), methyltransferase (mt), and tubulin-tyrosine ligase (ttl) encoded by genes BBOV_IV003210, BBOV_II003780, and BBOV_III004540 respectively. Quantitative PCR (qPCR) analyses showed these genes were upregulated in induced in vitro sexual stages and tick specific stages during parasite development in tick midgut. CDPK4 is conserved among apicomplexan parasites and shares 60% amino acid identity to previously identified Plasmodium falciparum CDPK4 that has been recognized as an essential protein for calcium signal transduction pathways, parasite sexual reproduction, and malaria parasite transmission. In addition, the data showed that xanthurenic acid (XA) is strongly involved in B. bovis sexual stage formation, XA is taken up by the red blood cell and transported through the erythrocyte cytoplasm where it induces parasitic egress from the infected red blood cell. Conclusions: B. bovis CDPK4 is predicted to play a vital role in sexual reproduction, and parasite transmission. Our findings in the present study will be useful for a better understanding of B. bovis biology, especially sexual stage development. Understanding the biology of the parasite and identifying target genes important for sexual reproduction will enable the production of non-transmissible live vaccines lacking genes required for sexual reproduction of the parasite using gene editing technologies, which might be an effective method of controlling bovine babesiosis.