Fig. 6
From: Left-right axis asymmetry determining human Cryptic gene is transcriptionally repressed by Snail
Proposed mechanism of Snail mediated L-R axis specification through Cryptic repression. (Up,left) Low endogenous expression of Snail on the left side of the developing embryo permits Cryptic-mediated Nodal signalling, causing left-side specification. (Up, right) Relatively higher levels of Snail on the right side suppress Cryptic-mediated Nodal signalling resulting right-side specification. (Bottom) A Snail mutant background is reported to aberrantly activate Nodal signalling. The de-repression of Cryptic in a mutant Snail background may cause bi-laterally symmetrical activation of Nodal signalling and thereby random organ positioning