A novel reporter rat strain that expresses LacZ upon Cre‐mediated recombination

Abstract

The recent widespread application of Cre/loxP technology has resulted in a new generation of conditional animal models that can better recapitulate many salient features of human disease. These models benefit from the ability to monitor the expression and functionality of Cre protein. We have generated a conditional (Cre/loxP dependent) LacZ reporter rat (termed the LacZ541 rat) to monitor Cre in transgenic rats. When LacZ541 rats were bred with another transgenic rat line expressing Cre recombinase under the control of the CAG promoter, LacZ/Cre double transgenic embryos displayed ubiquitous expression of LacZ, and when LacZ541 rats were bred with transgenic rats expressing Cre/loxP-dependent oncogenic H- or K-ras, LacZ was expressed in the lesions resulting from the activation of the oncogene. The LacZ541 rat enables evaluation of the performance of Cre-expressing systems which are based upon transgenic rats or somatic gene transfer vectors and provides efficient and simple lineage marking.

A novel conditional ZsGreen-expressing transgenic reporter rat strain for validating Cre recombinase expression

“…Table 1 summarizes the results. Similar to the expression patterns reported when NCre rats were mated to a LacZ reporter rat (SD-Tg(CAG-lacZ)541Htsu) 11 , no expression was seen in liver and spleen perhaps due to lack of or low CAG promoter activity in these tissues. While the CAG promoter is commonly used for ensuring ubiquitous and robust expression, low expression of transgenes under control of this promoter have been noted in some organs in other transgenic rat strains 12 .…”

Rat N-ERC/Mesothelin as a Marker for In Vivo Screening of Drugs against Pancreas Cancer

“…To determine whether serum levels of N-ERC/mesothelin correlated with tumor size, we assayed N-ERC/mesothelin levels in homozygous Kras301 rats bearing pancreas ductal adenocarcinomas. Adult male homozygous Kras301 rats were killed 4 weeks after injection of recombinant AxCANCre into the pancreatic duct via the common bile duct: see Fukamachi et al 2013 [22] for a detailed description of AxCANCre-mediated activation of the Kras oncogene in Kras301 rats. Many grossly visible whitish tumor nodules were observed throughout the pancreas in the transgenic rats.…”

“…Cre-expressing adenovirus vectors were amplified in HEK293 cells and then purified using Vivapure Adenopack (Vivascience, Hannover, Germany) as previously reported [17] . Pancreas tumors were induced as described previously [16] – [22] . The pancreas was fixed in 4% paraformaldehyde and processed for histological observation.…”

A Novel Reporter Rat Strain That Conditionally Expresses the Bright Red Fluorescent Protein tdTomato

“…Until now, a floxed STOP LacZ reporter rat was the only relevant line that adopted a Cre/loxP recombination system [ 30 ]. However, its application to living tissues and animals or for the three-dimensional imaging of relatively large tissue volumes is challenging, because histochemical processing is essential to visualize the Cre-expressing cells in sections.…”