Authors:R. L. Katona, I. Cserpán, K. Fátyol, Erika Csonka, and G. Hadlaczky
Transgenic mice are suitable model animals for testing the in vivo functionality of custom-tailored ribozymes. Transgenic experiments can demonstrate whether a ribozyme is able to cleave any RNA transcript of the host animal or not. Most probably, this kind of cleavage activity gives rise to phenotypic alterations in mice. In the present paper we demonstrate that an anti-HIV ribozyme does not cause any detectable phenotypic effect in mice carrying and expressing it. Our transgenic mice developed well and were indistinguishable from their wild type counterparts.
Authors:Anna Tóth, Katalin Fodor, P. Blazsó, I. Cserpán, Tünde Praznovszky, V. Tubak, A. Udvardy, Gy. Hadlaczky, and R. Katona
Direct reprogramming of mouse fibroblasts into induced pluripotent stem cells (iPS) was achieved recently by overexpression of four transcription factors encoded by retroviral vectors. Most of the virus vectors, however, may cause insertional mutagenesis in the host genome and may also induce tumor formation. Therefore, it is very important to discover novel and safer, non-viral reprogramming methods. Here we describe the reprogramming of somatic cells into iPS cells by a novel protein-based technique. Engineered Oct4, Sox2 and Klf4 transcription factors carrying an N-terminal Flag-tag and a C-terminal polyarginine tail were synthesized by a recently described mammalian artificial chromosome expression system (ACEs). This system is suitable for the high-level production of recombinant proteins in mammalian tissue culture cells. Recombinant proteins produced in this system contain all the post-translational modifications essential for the stability and the authentic function of the proteins. The engineered Oct4, Sox2 and Klf4 proteins efficiently induced the reprogramming of mouse embryonic fibroblasts by means of protein transduction. This novel method allows for the generation of iPS cells, which may be suitable for therapeutic applications in the future.