| First Author | Biben C | Year | 1997 |
| Journal | Genes Dev | Volume | 11 |
| Issue | 11 | Pages | 1357-69 |
| PubMed ID | 9192865 | Mgi Jnum | J:41048 |
| Mgi Id | MGI:892786 | Doi | 10.1101/gad.11.11.1357 |
| Citation | Biben C, et al. (1997) Homeodomain factor Nkx2-5 controls left/right asymmetric expression of bHLH gene eHand during murine heart development. Genes Dev 11(11):1357-69 |
| abstractText | One of the first morphological manifestations of left/right (L/R) asymmetry in mammalian embryos is a pronounced rightward looping of the linear heart tube. The direction of looping is thought to be controlled by signals from an embryonic L/R axial system. We report here that morphological L/R asymmetry in the murine heart first became apparent at the linear tube stage as a leftward displacement of its caudal aspect. Beginning at the same stage, the basic helix-loop-helix (bHLH) factor gene eHand was expressed in a strikingly left-dominant pattern in myocardium, reflecting an intrinsic molecular asymmetry. In hearts of embryos lacking the homeobox gene Nkx2-5, which do not loop, left-sided eHand expression was abolished. However, expression was unaffected in Sc1-/- hearts that loop poorly because of hematopoietic insufficiency, and was right-sided in hearts of inv/inv embryos that display situs inversus. The data predict that eHand expression is enhanced in descendants of the left heart progenitor pool as one response to inductive signaling from the L/R axial system, and that eHand controls intrinsic morphogenetic pathways essential for looping. One aspect of the intrinsic response to L/R information falls under Nkx2-5 homeobox control. |
