Unraveling the Complexity of the Rhomboid Serine Protease 4 Family of <i>Babesia bovis</i> Using Bioinformatics and Experimental Studies
Romina Gallenti,
Hala E. Hussein,
Heba F. Alzan,
Carlos E. Suarez,
Massaro Ueti,
Sebastián Asurmendi,
Daniel Benitez,
Flabio R. Araujo,
Peter Rolls,
Kgomotso Sibeko-Matjila,
Leonhard Schnittger,
Mónica Florin-Christensen
Affiliations
Romina Gallenti
Instituto de Patobiología Veterinaria (IPVET), Centro de Investigaciones en Ciencias Veterinarias y Agronómicas, Instituto Nacional de Tecnología Agropecuaria—Consejo Nacional de Investigaciones Científicas y Técnicas (INTA-CONICET), Hurlingham 1686, Argentina
Hala E. Hussein
Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA
Heba F. Alzan
Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA
Carlos E. Suarez
Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA
Massaro Ueti
Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA
Sebastián Asurmendi
Instituto de Agrobiotecnología y Biología Molecular (IABiMo), Instituto Nacional de Tecnología Agropecuaria—Consejo Nacional de Investigaciones Científicas y Técnicas (INTA-CONICET), Hurlingham 1686, Argentina
Daniel Benitez
Estación Experimental Agropecuaria (EEA)-Mercedes, Instituto Nacional de Tecnología Agropecuaria (INTA), Mercedes 3470, Argentina
Flabio R. Araujo
EMBRAPA Beef Cattle, Campo Grande 79106-550, Brazil
Peter Rolls
Department of Agriculture & Fisheries, Tick Fever Centre, Wacol, QLD 4076, Australia
Kgomotso Sibeko-Matjila
Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa
Leonhard Schnittger
Instituto de Patobiología Veterinaria (IPVET), Centro de Investigaciones en Ciencias Veterinarias y Agronómicas, Instituto Nacional de Tecnología Agropecuaria—Consejo Nacional de Investigaciones Científicas y Técnicas (INTA-CONICET), Hurlingham 1686, Argentina
Mónica Florin-Christensen
Instituto de Patobiología Veterinaria (IPVET), Centro de Investigaciones en Ciencias Veterinarias y Agronómicas, Instituto Nacional de Tecnología Agropecuaria—Consejo Nacional de Investigaciones Científicas y Técnicas (INTA-CONICET), Hurlingham 1686, Argentina
Babesia bovis, a tick-transmitted apicomplexan protozoon, infects cattle in tropical and subtropical regions around the world. In the apicomplexans Toxoplasma gondii and Plasmodium falciparum, rhomboid serine protease 4 (ROM4) fulfills an essential role in host cell invasion. We thus investigated B. bovis ROM4 coding genes; their genomic organization; their expression in in vitro cultured asexual (AS) and sexual stages (SS); and strain polymorphisms. B. bovis contains five rom4 paralogous genes in chromosome 2, which we have named rom4.1, 4.2, 4.3, 4.4 and 4.5. There are moderate degrees of sequence identity between them, except for rom4.3 and 4.4, which are almost identical. RT-qPCR analysis showed that rom4.1 and rom4.3/4.4, respectively, display 18-fold and 218-fold significantly higher (p rom4.4 and 4.5 differed non-significantly between the stages. ROM4 polymorphisms among geographic isolates were essentially restricted to the number of tandem repeats of a 29-amino acid sequence in ROM4.5. This sequence repeat is highly conserved and predicted as antigenic. B. bovis ROMs likely participate in relevant host–pathogen interactions and are possibly useful targets for the development of new control strategies against this pathogen.
