• Journal of Microbiology and Biotechnology
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• 제18권7호
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• pp.1342-1351
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• 2008

The feasibility of the use of Flp-mediated cassette exchange in the development of a CHO cell line, which produces erythropoietin (EPO) stably and largely, was investigated. A stable, high enhanced green fluorescence protein (EGFP)-producing clone was screened by extensive flow cytometric analysis. An EPO expression unit was targeted into the premarked locus of the stable parental clone by Flp-mediated cassette exchange and a correctly targeted clone (FC28T7) was obtained. The EPO production of FC28T7 was proven to be stable in long-term culture. Furthermore, the Flp-mediated cassette exchange did not alter the stable parental clone's characteristics concerning transgene expression level and stability. Taken together, the data obtained here indicated that the establishment of CHO cell lines stably producing a desired protein is achievable using Flp-mediated cassette exchange.

• 미생물학회지
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• 제25권3호
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• pp.198-204
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• 1987

P. pulida KU218R-3와 P. Putida KU42엠 원형질체 혼합액에 PEG 6000을 처리하여 biparental형과 recombinant형의 융합체를 얻었다. Pseudomonasd의 원형질체가 융합하는 형태는 TEM으로 관찰하였고, 원형질 융합체의 선별은 항생제 내성을 유전적 지표로 하여 간접적인 방법으로 선별하였다. Pseudomonas의 원형질체 융합에는 40% (w / v) PEG 6000을 상온에서 10분간 처리하는 것이 가장 효과적이었으나 PEG를 처리하지 않은 실험구에서도 융합체가 4%의 빈도로 생성되므로 PEG의 효과는 절대적인 것이 아니었다. 생성된 융합체의 대부분은 biparental clone이었고 (10.4%), recombinant clone의 생성빈도 는 너무 낮았디 (0.12%). 또한 biparental clone의 대부분은 further propagation 증에 모균주의 형태로 분리되었고, 이 과정 에서 late recombinant플 생성하였다. biparental clone에 t얀해 rE'combinant clonE은 여러 셔1대 후에도 안정하였다.

• Asian Pacific Journal of Cancer Prevention
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• 제13권9호
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• pp.4827-4834
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• 2012

Tumor suppressor genes have received much attention for their roles in the development of human malignancies. Gelsolin has been found to be down-regulated in several types of human cancers, including leukemias. It is, however, expressed in macrophages, which are the final differentiation derivatives for the monocytic myeloid lineage, implicating this protein in the differentiation process of such cells. In order to investigate the role of gelsolin in leukaemic cell differentiation, stable clones over-expressing ectopic gelsolin, and a control clone were established from U937 leukaemia cells. Unlike the control cells, both gelsolin-overexpressing clones displayed retarded growth, improved monocytic morphology, increased NADPH and NSE activities, and enhanced surface expression of the ${\beta}$-integrin receptor, CD11b, when compared with the parental U937 cells. Interestingly, RT-PCR and western blot analysis also revealed that gelsolin enhanced p21CIP1 mRNA and protein expression in the overexpressing clones. Moreover, transient transfection with siRNA silencing P21CIP1, but not the control siRNA, resulted in a reduction in monocytic differentiation, accompanied by an increase in proliferation. In conclusion, our work demonstrates that gelsolin, by itself, is capable of inducing monocytic differentiation in U937 leukaemia cells, most probably through p21CIP1 activation.