[Researches on the nucleotide sequencing of the recombinant Sj 22.6 kDa antigen gene of Schistosoma japonicum].
OBJECTIVE
To sequence the cloned gene in pGSj24 and to identify the encoded protein.


METHODS
The cloned gene in pGSj24 was digested from the recombinant plasmid by EcoRI, ligated into the M13mp19 vector and sequenced by automatic sequencer. The sequence was analyzed by Goldkey DNA and Protein Analytical Program and DNASIS Program.


RESULTS
The pGSj24 cloned gene was demonstrated to be 840 bp containing one opened reading frame (ORF) with an initiation codon ATG at position 23 nt and a termination codon TAA at position 596 nt, encoding a protein with a molecular weight of 22.6 kDa. At the upstream and downstream of the ORF there were termination codons, so the encoded protein was unable to be larger. However, there was a termination codon TAA at position 11 nt, suggesting why the 22.6 kDa protein expressed separately. The nucleotide sequence of the pGSj24 cloned gene shared 95% identity with that of the corresponding part of S. japonicum 22.6 kDa antigen gene, and 99.7% identity in the encoding part. The deduced amino acid sequence analysis showed a sequence motif known as EF-Hand calcium binding domain, several endoplasmic reticulum targeting sequences and microbodies C-terminal targeting signals. The possible antigen determinants were predicted within the amino acid fragments of 29-32aa, 63-68aa and 87-101aa.


CONCLUSIONS
The cloned gene in pGSj24 is the gene that encodes Sj22.6 kDa antigen.
Zhang
G
G
Department of Parasitology, Nanjing Medical University, Nanjing 210029.
Zhang
Z
Z
Chen
S
S
Shen
Y
Y
Wu
H
H
Su
C
C
Wang
R
R
Wu
G
G
D000595:Amino Acid Sequence; D000818:Animals; D000947:Antigens, Helminth / Q000235:genetics*; D001483:Base Sequence; D018509:DNA, Helminth / Q000235:genetics; D017238:Genes, Helminth; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000235:genetics; D012549:Schistosoma japonicum / Q000235:genetics* / Q000276:immunology
C087430:22.6-kDa antigen, Schistosoma japonicum; D000947:Antigens, Helminth; D018509:DNA, Helminth; D008565:Membrane Proteins; D011994:Recombinant Proteins