[Sequence analysis and expression of GRA7 gene of Toxoplasma gondii isolates in Escherichia coli].
OBJECTIVE
To analyze the difference of GRA7 gene of Toxoplasma gondii different isolated strains and express GRA7 in Escherichia coli.


METHODS
The GRA7 gene was amplified from genomes of T. gondii isolates by PCR and was cloned into pGEX-4T-1. The recombinant plasmid was transformed into JM109 and sent to be sequenced. The sequence was analyzed with CLUSTALW (an internet tool). The recombinant plasmid was induced by IPTG to express the fusion protein,which was identified by SDS-PAGE and Western blot with positive sera. The protein was purified and used as a diagnostic antigen for ELISA to test serum samples.


RESULTS
There was no difference among the sequences of T. gondii GRA7 gene from different isolates. The recombinant plasmid pGEX-4T-1/GRA7 induced by IPTG was expressed in E. coli. It was a GST fusion protein and could react with human and rabbit positive sera analyzed by Western blot.


CONCLUSIONS
The GRA7 gene of T. gondii isolates is highly conservative. The GRA7 is expressed as a recombinant protein in Escherichia coli, which shows an immunoreactivity.
Zheng
Bin
B
Department of Parasitology, Zhongshan Medical College,Sun Yat-sen University, Guangzhou 510080, China.
Zheng
Huan-Qin
HQ
He
Ai
A
Li
Zhuo-Ya
ZY
Cao
Ai-Lian
AL
Zhang
Rui-Lin
RL
Zhan
Xi-Mei
XM
D000818:Animals; D000953:Antigens, Protozoan / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D001483:Base Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D005982:Glutathione Transferase / Q000235:genetics; D008969:Molecular Sequence Data; D015800:Protozoan Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis* / Q000276:immunology; D014122:Toxoplasma / Q000235:genetics* / Q000276:immunology
D000953:Antigens, Protozoan; C112573:GRA7 protein, Toxoplasma gondii; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D005982:Glutathione Transferase