Targeting and tracing cardiac myocytes with Fgf1 expression in F1A‐CreERT2 transgenic mice

Abstract

Fibroblast growth factor 1 (FGF1) regulates many biological and physiological processes. In mice, Fgf1 gene contains at least three upstream promoters and spliced to the first protein coding exon alternatively, giving rise to different Fgf1 mRNA variants (1A, 1B and 1G). Among them, the Fgf1A transcript is predominantly expressed in heart. FGF1 can induce cardiomyocyte regeneration and cardiogenesis in vitro and in vivo. Here, we generated a novel mouse line Fgf1A promoter (F1A)‐driven inducible Cre recombinase (CreERT2). We firstly demonstrated that the highest mRNA expression of CreERT2 were detected in the heart specifically of F1A‐CreERT2 founder mice, similar to that of Fgf1A mRNA. The F1A‐CreERT2 mice were crossed with ROSA26R mice, and the F1 mice were analyzed. The punctate blue LacZ‐positive signals were detected exclusively in the heart after tamoxifen administration. The CreERT2‐mediated recombination in the tissues is monitored through punctate blue LacZ‐positive signals, indicating the in situ localization of F1A‐positive cells. Interestingly, these F1A‐positive cells with punctate blue signals were colocalized with cardiomyocytes expressing a‐actinin, a‐myosin heavy chain and cardiac troponin T, suggesting cardiomyocyte‐specific expression of Fgf1A. Our data suggested that the F1A‐CreERT2 mouse line could be used for time‐dependent and lineage tracing of Fgf1‐expressing cells in vivo.Support or Funding InformationMinistry of Science and Technology, Taiwan;Ministry of Health and Welfare, Taiwan;National Health Research Institutes, TaiwanThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.