Homeodomain factor Nkx2-5 controls left/right asymmetric expression of bHLH gene eHand during murine heart development
Author(s)
Biben, C; Harvey, RP;
Details
Publication Year 1997-06-01, Volume 11, Issue #11, Page 1357-1369
Journal Title
GENES & DEVELOPMENT
Publication Type
Journal Article
Abstract
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.
Publisher
COLD SPRING HARBOR LAB PRESS, PUBLICATIONS DEPT
Keywords
EMBRYONIC HEART; MOUSE EMBRYOS; TRANSCRIPTION FACTOR; CHICK HEART; DIFFERENTIATION; EMBRYOGENESIS; DROSOPHILA; INDUCTION; MESODERM; ENDODERM
Rights Notice
Refer to copyright notice on published article.


Creation Date: 1997-06-01 12:00:00
Last Modified: 0001-01-01 12:00:00
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