Dataset: GPR21 KO mice demonstrate no resistance to high fat diet induced obesity or improved glucose tolerance ------------------------------------------------------------------------ **Abstract** *Gpr21* KO mice generated with *Gpr21* KO ES cells obtained from Deltagen showed improved glucose tolerance and insulin sensitivity when fed a high fat diet. Further mRNA expression analysis revealed changes in *Rabgap1* levels and raised the possibility that *Rabgap1* gene may have been modified. To assess this hypothesis a new *Gpr21* KO mouse line using TALENS technology was generated. *Gpr21* gene deletion was confirmed by PCR and *Gpr21* and *Rabgap1* mRNA expression levels were determined by RT-PCR. The newly generated *Gpr21* KO mice when fed a normal or high fat diet chow did not maintain their improved metabolic phenotype. In conclusion, *Rabgap1* disturbance mRNA expression levels may have contributed to the phenotype of the originally designed *Gpr21* KO mice. Read the [full-text publication][1] by Wang, Pan, Baribault, Chui, Gundel, and Véniant (*F1000Research*, 2016) for more details. **Data availability** [Figure 1B raw data: Rabgap1 microarray expression data from Geltagen Gpr21 KO mice.][2] [Figure 2C raw data: Uncropped gel image.][3] [Figure 2D raw data: Gpr21 expression in Gpr21 TAL 29bp mice using probe in deletion region.][4] [Figure 3A raw data: qPCR for Gpr21 TAL 29bp mice using Rabgap1 probes.][5] [Figure 3B raw data: qPCR for Gpr21 TAL 29bp mice Strbp expression.][6] [Figure 4 raw data: Metabolic phenotype of Gpr21 TAL 29bp mice.][7] [1]: http://dx.doi.org/10.12688/f1000research.7822.1 [2]: https://osf.io/drtxp/ [3]: https://osf.io/fdgq5/ [4]: https://osf.io/ra42b/ [5]: https://osf.io/fngeh/ [6]: https://osf.io/dvtmh/ [7]: https://osf.io/akwfm/