[Chromosome aberration and carcinogenicity of CHO dhfr- cells transformed by plasmid containing S+ and Pre S1 of fusion gene of hepatitis B virus].
OBJECTIVE
To investigate the chromosome aberrations and carcinogenicity of CHO-dhfr- cell induced by integration of plasmid containing S+ and Pre S1 fusion gene of hepatitis B surface antigen (HBsAg).


METHODS
The plasmid pCHBSS1G was constructed with S+ Pre S1 of HBsAg. CHO-dhfr- cells were transformed with this recombinant plasmid DNA and CHO cells lines with integrated DNA were cloned and named GdSS118. The GdSS1 18 cell lines secreting the S+ Pre S1 fusion protein of HBsAg at high level were developed by screening in increased concentration of MTX and MSX in cultured media. To make sample of cells chromosome, the cells integrated DNA were subcutaneously injected into nude mouse.


RESULTS
The CHO-dhfr- cell lines integrated with S and Pre S1 fusion protein of HBsAg were developed and named GdSS1-18 cell lines. The frequencies and type of chromosome aberrations of the GdSS1-18 cell lines with different passage generations were 11%, 56% and 29%, respectively, while that of the control CHO-dhfr- cell lines was 6%. There was no change in the mode of chromosomes, both cell lines having 20 chromosome s. Both cell lines were non-oncogenic in nude mouse.


CONCLUSIONS
The chromosome aberration of CHO-dhfr- cells with integrated DNA were obviously higher than that of the original CHO-dhfr- cells without integrated DNA. Both cell lines were non oncogenic in nude mouse.
Tian
S F
SF
Institute of Virology, Chinese Academy of Preventive Medicine, Beijing 100052, China.
Ruan
W Q
WQ
Wang
X P
XP
Zhang
L L
LL
Yang
F R
FR
Zong
F
F
Ruan
L
L
D000818:Animals; D016466:CHO Cells / Q000201:enzymology / Q000378:metabolism*; D002471:Cell Transformation, Neoplastic; D002472:Cell Transformation, Viral; D002869:Chromosome Aberrations; D006224:Cricetinae; D003412:Cricetulus; D006514:Hepatitis B Surface Antigens / Q000235:genetics*; D006801:Humans; D011498:Protein Precursors / Q000235:genetics*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics; D014759:Viral Envelope Proteins / Q000235:genetics; D014760:Viral Fusion Proteins / Q000235:genetics
D006514:Hepatitis B Surface Antigens; D011498:Protein Precursors; D011994:Recombinant Proteins; D014759:Viral Envelope Proteins; D014760:Viral Fusion Proteins; C050806:presurface protein 1, hepatitis B surface antigen; D013762:Tetrahydrofolate Dehydrogenase