Clin Res Cardiol 100, Suppl 1, April 2011

P651 - Knockdown of the orphan G protein-coupled receptor 126 reduces heart rate and influences ventricular morphogenesis in zebrafish
M. J. van Amerongen1, C. Patra1, S. Ghosh1, B. Jungblut1, F. Engel1
1Herz- und Lungenforschung, Max-Planck-Institut für, Bad Nauheim;
Gpr126 is an orphan G protein-coupled receptor (GPCR). The lack of knowledge regarding its natural or synthetic ligands makes it difficult to determine its biological function. Based on an mRNA expression screen we have identified gpr126 as a gene that is transiently expressed during embryonic rat heart development. gpr126 mRNA is highest expressed in the heart from E13.5 to E17.5 and declines thereafter. RT-PCR showed that Gpr126 displays a similar transient expression pattern in the developing mouse heart. In addition, RT-PCR showed that gpr126 mRNA is also expressed in the zebrafish embryo, demonstrating that Gpr126 is highly conserved in vertebrates. gpr126 mRNA is absent in the early zebrafish embryo (1 and 9 hours post fertilization (hpf)) and its expression starts around 24 hpf. By in situ hybridization at 44 hpf, we observed expression of gpr126 mRNA in the heart ventricle and atrium. To investigate how gpr126 may function in heart development we injected translation- and splice-inhibiting morpholino antisense oligonucleotides (MOatg and MOsplice respectively) to knockdown gpr126 in zebrafish embryos. MOsplice resulted in deletion of exon 13 which was readily detectable by RT-PCR at 80h hpf. Following injection of either MOatg or MOsplice, cmcl2-GFP transgenic embryos exhibiting heart specific fluorescence were collected from different stages and screened for morphological and functional defects. gpr126 knockdown resulted in a significantly reduced heart rate and blood accumulation between the sinus venosus and the atrium, which was first observed around 34 hpf. Furthermore, at 56 hpf gpr126 knockdown embryos exhibited a dysmorphic ventricle and apparent cardiac edema with otherwise normal overall morphology. At the moment we are investigating the function of Gpr126 in mice using a knockout strain. Mice lacking Gpr126 are embryonic lethal and die between embryonic day 10 and 12, indicating that Gpr126 has a non-redundant vital function in development. In conclusion, this study reveals an essential role for gpr126 in cardiac development.
Clin Res Cardiol 100, Suppl 1, April 2011
Zitierung mit Vortrags- oder Posternummer s.o.
DOI 10.1007/s00392-011-1100-y