Dev Dyn 2008 Dec 01;23712:3557-64. doi: 10.1002/dvdy.21638.

Left-asymmetric expression of Galanin in the linear heart tube of the mouse embryo is independent of the nodal co-receptor gene cryptic.

Abstract
Only very few left/right asymmetrically expressed genes are known in the mammalian embryo. In a screen for novel factors we identified the gene encoding the neuropeptide Galanin in mouse. At embryonic day (E) 8.5 asymmetric mRNA transcription was found in the left half of the linear heart tube. During heart looping and morphogenesis expression became restricted to the atrio-ventricular (AV) canal, followed by specific staining of the AV-node and AV-rings in the four-chambered heart. Expression was inverted in inv/inv and randomized in homozygous iv mutant embryos. Left-sided heart-specific transcription of mouse Gal thus should be controlled by the left-right pathway. The asymmetric pattern was retained in cryptic mutant embryos, in which the Nodal signaling cascade is disrupted. Surprisingly, Pitx2c was found to be expressed in 50% of cryptic mutant hearts as well, suggesting that some aspects of asymmetric gene expression in the heart are independent of cryptic.

PubMed ID: 18773496
Article link: Dev Dyn


Species referenced: Xenopus laevis
Genes referenced: gal gal.2 nodal nodal1 pitx2 tdgf1


Article Images: [+] show captions