Identification and characterization of a shrimp white spot syndrome virus (WSSV) gene that encodes a novel chimeric polypeptide of cellular-type thymidine kinase and thymidylate kinase.
From previously constructed genomic libraries of a Taiwan WSSV isolate, a putative WSSV tk-tmk gene was identified. Uniquely, the open reading frame (ORF) of this gene was predicted to encode a novel chimeric protein of 388 amino acids with significant homology to two proteins: thymidine kinase (TK) and thymidylate kinase (TMK). Northern blot analysis with a WSSV tk-tmk-specific riboprobe detected a major transcript of 1.6 kb. When healthy adult Penaeus monodon shrimp were inoculated with WSSV, the tk-tmk gene transcript was first detected by RT-PCR analysis at 4 h postinfection and transcription levels continued to increase over the first 18 h. The gene's major in vitro transcription and translation product, equivalent to the predicted size (43 kDa), is a single chimeric protein that includes both the TK and TMK functional motifs. Evidence for phylogenetic analysis and sequence alignment suggested that the gene may have resulted from the fusion of a cellular-type TK gene and a cellular-type TMK gene. Its unique arrangement may also provide a valuable gene marker for WSSV.
Tsai
M F
MF
Department of Zoology, Institute of Biochemistry, Taipei, 106, Taiwan, Republic of China.
Yu
H T
HT
Tzeng
H F
HF
Leu
J H
JH
Chou
C M
CM
Huang
C J
CJ
Wang
C H
CH
Lin
J Y
JY
Kou
G H
GH
Lo
C F
CF
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004267:DNA Viruses / Q000145:classification* / Q000201:enzymology / Q000235:genetics*; D033364:Decapoda / Q000821:virology*; D005814:Genes, Viral; D008969:Molecular Sequence Data; D009703:Nucleoside-Phosphate Kinase / Q000737:chemistry / Q000235:genetics*; D010766:Phosphorylation; D010802:Phylogeny; D014176:Protein Biosynthesis; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013937:Thymidine Kinase / Q000737:chemistry / Q000235:genetics*; D014158:Transcription, Genetic; D015678:Viral Structural Proteins / Q000235:genetics*
D011993:Recombinant Fusion Proteins; D015678:Viral Structural Proteins; D013937:Thymidine Kinase; D009703:Nucleoside-Phosphate Kinase; C020093:dTMP kinase