TaCRK3 encodes a novel Theileria annulata protein kinase with motifs characteristic of the family of eukaryotic cyclin dependent kinases: a comparative analysis of its expression with TaCRK2 during the parasite life cycle.
The TaCRK3 gene from the bovine apicomplexan parasite Theileria annulata, encodes a 46 kDa polypeptide with strong homology to the eukaryotic family of cyclin-dependent kinases. TaCRK3 does not show significant alignment with any particular CDK group, other than the Pfmrk kinases from the related apicomplexans Plasmodium falciparum and Plasmodium yoelii. It has a putative bipartite nuclear localization signal and is located to parasite nuclei by IFAT. Protein levels are constitutive throughout differentiation of the intra-lymphocytic macroschizont. This contrasts with the expression pattern of TaCRK2 (Kinnaird et al., 1996, Mol. Microbiol., 22, 293-302) which is closely related to the eukaryotic CDK1 /2 families involved in regulation of cell cycle progression. TaCRK2 is also located to the parasite nuclei but has no nuclear localization signal and exhibits transient up-regulation in protein levels during mid-merogony. However compared to TaCRK3, it shows down-regulation near the end of merogony. We predict that TaCRK3 may have a role in regulation of gene transcription while TaCRK2 is more likely to be involved in control of parasite nuclear division.
Kinnaird
J
J
Department of Veterinary Parasitology, Glasgow University, Bearsden Road, Glasgow G61 1QH, UK. j.kinnaird@vet.gla.ac.uk
Logan
M
M
Tait
A
A
Langsley
G
G
D020816:Amino Acid Motifs / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D016203:CDC2 Protein Kinase; D002417:Cattle; D002460:Cell Line; D018844:Cyclin-Dependent Kinases / Q000235:genetics*; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D005057:Eukaryotic Cells / Q000201:enzymology / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D008969:Molecular Sequence Data; D011494:Protein Kinases / Q000235:genetics; D015800:Protozoan Proteins / Q000235:genetics; D016053:RNA, Protozoan / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D016796:Theileria annulata / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D013801:Theileriasis / Q000201:enzymology / Q000469:parasitology
C077833:CRK protein, protozoan; D018076:DNA, Complementary; D015800:Protozoan Proteins; D016053:RNA, Protozoan; D011494:Protein Kinases; D016203:CDC2 Protein Kinase; D018844:Cyclin-Dependent Kinases