Bento Fernanda Mara, Takeshita Daniela, Sacramento Chester Bittencourt, Machado Tamara Rocha, Mathor Monica Beatriz, Carmona Adriana Karaoglanovic, Han Sang Won
Department of Biophysics & Center for Gene Therapy, UNIFESP - EPM, São Paulo, SP, Brazil.
BMC Biotechnol. 2004 Dec 2;4:29. doi: 10.1186/1472-6750-4-29.
The blasticidin S resistance gene (bsr) is a selectable marker used for gene transfer experiments. The bsr gene encodes for blasticidin S (BS) deaminase, which has a specific activity upon BS. Therefore, its expression is supposed to be harmless in cells. The work reported on herein consisted of experiments to verify a possible toxicity of bsr on mammalian cells, which include several cell lines and primary cultures.
Murine keratinocyte BALB/MK and human primary keratinocyte cells transduced with the retroviral vector LBmSN, which has an improved expression system of bsr, namely bsrm, died in five days after the transduction. Meanwhile the control vector LBSN, which expresses bsr, did not provoke cell death. The lethal activity of bsrm was observed only in human keratinocytes and BALB/MK cells among the cell types tested here. Death appears to be mediated by a factor, which is secreted by the BALB/MK transduced cells.
By our study we demonstrated that the expression of bsrm gene is toxic to human keratinocytes and BALB/MK cells. It is likely over expression of BS deaminase gene is responsible for the death.
杀稻瘟菌素S抗性基因（bsr）是用于基因转移实验的选择标记。bsr基因编码杀稻瘟菌素S（BS）脱氨酶，其对BS具有特定活性。因此，其表达在细胞中应该是无害的。本文报道的工作包括验证bsr对哺乳动物细胞（包括几种细胞系和原代培养物）可能的毒性的实验。
用具有改进的bsr表达系统即bsrm的逆转录病毒载体LBmSN转导的小鼠角质形成细胞BALB/MK和人原代角质形成细胞在转导后五天死亡。同时，表达bsr的对照载体LBSN未引起细胞死亡。在此测试的细胞类型中，仅在人角质形成细胞和BALB/MK细胞中观察到bsrm的致死活性。死亡似乎由转导的BALB/MK细胞分泌的一种因子介导。
通过我们的研究，我们证明bsrm基因的表达对人角质形成细胞和BALB/MK细胞有毒性。可能是BS脱氨酶基因的过表达导致了细胞死亡。
