Conditional gene expression systems in the transgenic rat brain

Abstract

BackgroundTurning gene expression on and off at will is one of the most powerful tools for the study of gene function in vivo. While several conditional systems were successful in invertebrates, in mice the Cre/loxP recombination system and the tet-controlled transcription activation system are predominant. Both expression systems allow for spatial and temporal control of gene activities, and, in the case of tet regulation, even for the reversible activation/inactivation of gene expression. Although the rat is the principal experimental model in biomedical research, in particular in studies of neuroscience, conditional rat transgenic systems are exceptionally rare in this species.ResultsWe addressed this lack of technology, and established and thoroughly characterized CreERT2 and tTA transgenic rats with forebrain-specific transgene expression, controlled by the CaMKII alpha promoter. In addition, we developed new universal rat reporter lines for both transcription control systems and established inducible and efficient reporter gene expression in forebrain neurons.ConclusionsWe demonstrate that conditional genetic manipulations in the rat brain are both feasible and practicable and outline advantages and limitations of the Tet and Cre/loxP system in the rat brain.

Beware of your Cre‐Ation: lacZ expression impairs neuronal integrity and hippocampus‐dependent memory

“…Although GFP‐related toxicity has been previously reported (Ciesielska et al, ), we did not observe any phenotypic alterations following glutamatergic GFP expression or expression of the channelrhodopsin 2‐eYFP fusion product and would thus suggest the use of GFP or eYFP rather than lacZ as reporter proteins for future studies. Given the increasing possibilities of genetic manipulations also for rats and primates, as well as the wide‐spread use of lacZ as a reporter‐protein (Li et al, ; Tong et al, ; Diester et al, ; Skarnes et al, ; Witten et al, ; Schönig et al, ; White et al, ) as well as for the Daun02 method (Koya et al, ), we urge that reported effects are carefully controlled and that lacZ expression will be taken in to account as a contributing factor for any observed phenotypes.…”

Development of Transgenic Minipigs with Expression of Antimorphic Human Cryptochrome 1

“…In this report we describe the generation of Bama-minipigs holding a genomically integrated transcription cassette from which a heterologous and antimorphic CRY1 is expressed. The transgene is under the control of a CAG promoter which has shown almost ubiquitous activity in all tissues including the brain and skin [44], [45]. Expression of the transgene in the 23 live-born, seemingly healthy, cloned animals was verified by PCR and RT-qPCR on DNA and RNA, respectively, extracted from skin biopsies.…”

2015 Guidelines for Establishing Genetically Modified Rat Models for Cardiovascular Research

“…Plasmid-based transgenes and bacterial artificial chromosome (BAC)-based transgenes are routinely used in rats [10, 67–69] and BACs that are recombineered to carry Cre recombinase transgenes have recently been used to produce some of the first Cre transgenic models in rats [65, 68, 70]. Lentivirus-based transgenesis is another established technique in the rat [71, 72], although this transgenesis method is considerably less prevalent.…”