Objective      To detected the mRNA and protein expression of transcription factor Tbx18

and to reveal its spatiotemporal expression during mouse embryonic development.       Methods      The Tbx18 mRNA expression in whole embryo during mouse embryonic development was detected by whole mount in situ hybridization. The protein expression of reporter LacZ gene in Tbx18-Cre/Rosa26R/LacZ genetic lineage tracer model of mouse embryos was detected using X-gal staining. The mRNA expression Tbx18 in mouse embryonic heart were detected using fluorescence quantitative PCR.       Results      The Tbx18 signals of the E9.5 d to E10.5 d mouse embryos were mainly expressed in the proepicardium at first and then emigrated to the epicardium gradually. The Tbx18 signals of the E11.5 d to E12.5 d mouse embryos were mainly expressed in epicardium

forelimb bud and hindlimb bud

somite and mandibula/maxillar cleft region. Besides the regions above

the Tbx18 signals of the mouse embryos older than E12.5 d were also expressed in the kidney

ureter and bladder.       Conclusion      The expression of the transcription factor Tbx18 has spatiotemporal idiosyncrasy in mouse embryonic development. It may play a vital role in mouse heart development

and also in the development of kidney

ureter

bladder

somite

forelimb and hindlimb buds

and mandibular/maxillar cleft region.