Application of impermeable barriers combined with candidate factor soaked beads to study inductive signals in the chick

TY - JOUR

T1 - Application of impermeable barriers combined with candidate factor soaked beads to study inductive signals in the chick

AU - Wilde, Susan

AU - Logan, Malcolm P.

PY - 2016/11/17

Y1 - 2016/11/17

N2 - The chick embryo provides a superb vertebrate model that can be used to dissect developmental questions in a direct way. Its accessibility and robustness following surgical intervention are key experimental strengths. Mica plates were the first barriers used to prevent chick limb bud initiation1. Protocols that use aluminum foil as an impermeable barrier to wing bud or leg bud induction and or initiation are described. We combine this technique with bead placement lateral to the barrier to exogenously supply candidate endogenous factors that have been blocked by the barrier. The results are analyzed using in situ hybridization of subsequent gene expression. Our main focus is on the role of retinoic acid signaling in the induction and later initiation of the chick embryo fore and hindlimb. We use BMS 493 (an inverse agonist of retinoic acid receptors (RAR)) soaked beads implanted in the lateral plate mesoderm (LPM) to mimic the effect of a barrier placed between the somites (a source of retinoic acid (RA)) and the LPM from which limb buds grow. Modified versions of these protocols could also be used to address other questions on the origin and timing of inductive cues. Provided the region of the chick embryo is accessible at the relevant developmental stage, a barrier could be placed between the two tissues and consequent changes in development studied. Examples may be found in the developing brain, axis extension and in organ development, such as liver or kidney induction.

AB - The chick embryo provides a superb vertebrate model that can be used to dissect developmental questions in a direct way. Its accessibility and robustness following surgical intervention are key experimental strengths. Mica plates were the first barriers used to prevent chick limb bud initiation1. Protocols that use aluminum foil as an impermeable barrier to wing bud or leg bud induction and or initiation are described. We combine this technique with bead placement lateral to the barrier to exogenously supply candidate endogenous factors that have been blocked by the barrier. The results are analyzed using in situ hybridization of subsequent gene expression. Our main focus is on the role of retinoic acid signaling in the induction and later initiation of the chick embryo fore and hindlimb. We use BMS 493 (an inverse agonist of retinoic acid receptors (RAR)) soaked beads implanted in the lateral plate mesoderm (LPM) to mimic the effect of a barrier placed between the somites (a source of retinoic acid (RA)) and the LPM from which limb buds grow. Modified versions of these protocols could also be used to address other questions on the origin and timing of inductive cues. Provided the region of the chick embryo is accessible at the relevant developmental stage, a barrier could be placed between the two tissues and consequent changes in development studied. Examples may be found in the developing brain, axis extension and in organ development, such as liver or kidney induction.

KW - Chick embryo

KW - Developmental biology

KW - Gene expression

KW - Impermeable barriers

KW - Lateral plate mesoderm

KW - Limb induction

KW - Limb initiation

KW - Retinoic acid signaling

KW - Somites

KW - Tbx4

KW - Tbx5

UR - http://www.scopus.com/inward/record.url?scp=84998533013&partnerID=8YFLogxK

U2 - 10.3791/54618

DO - 10.3791/54618

M3 - Article

AN - SCOPUS:84998533013

SN - 1940-087X

VL - 2016

JO - Journal of Visualized Experiments

JF - Journal of Visualized Experiments

IS - 117

M1 - e54618

ER -