[Show abstract][Hide abstract] ABSTRACT: INTRODUCTION Sonoporation is a method for the introduction of genes into tissues such as those of chick embryos. It enables gene incorporation into target tissue by the combination of ultrasound exposure and subsequent rupture of microbubbles. Sonoporation has several advantages: (1) It is simple, involving two main steps-preparation of a microbubble-DNA mixture, followed by injection and ultrasound treatment of the target tissue; (2) it allows highly efficient gene incorporation into mesenchymal tissues; (3) it does not induce significant tissue damage-most of the sonoporated chick embryos survived without showing significant embryonic abnormalities or cell death; and (4) it can be used to introduce genes into several chick embryonic tissues (e.g., branchial arch and lateral plate mesoderm). To demonstrate the utility of sonoporation, an expression vector containing the Sonic hedgehog (Shh) gene was incorporated into the developing chick limb bud, leading to additional digit formation in the Shh-expressing embryos. Sonoporation may not be appropriate for the introduction of genes into tissues with cavitated or open structures. Sonoporation into the neural tube and limb ectoderm often resulted in dispersed gene expression due to diffusion of the injected microbubbles before ultrasound treatment. Despite these problems, sonoporation is a useful method for the analysis of gene function(s) in vivo and brings a new area of gene transfer to medical, molecular, and developmental biology. This protocol describes the use of sonoporation to introduce vectors into embryonic chick limb bud.
Full-text · Article · Mar 2011 · Cold Spring Harbor Protocols
[Show abstract][Hide abstract] ABSTRACT: External genitalia are anatomical structures located at the posterior embryonic region as part of several urogenital/reproductive organs. The embryonic anlage of the external genitalia, the genital tubercle (GT) develops as a bud-shaped structure with an initial urethral plate and later urethra. Embryonic external genitalia are considered to be one of the appendages. Recent experiments suggest that essential regulatory genes possess similar functions for the outgrowth regulation of the GT and limb appendages. The transient embryonic epithelia located in the distal GT are called the distal urethral epithelium (DUE) regulating, at least in part, the (distal) GT development. This review covers the available data about early patterning of GT and discusses the molecular developmental similarities and points of divergence between the different appendages. Development of the male and female external genitalia is also reviewed.
[Show abstract][Hide abstract] ABSTRACT: Msx1 and Msx2 genes encode the homeodomain transcription factors. Several gene knockout mice and expression studies suggest that they possess functionally redundant roles in embryogenesis. In this study, we revealed that Msx1 and Msx2 were expressed during ventral body wall formation in an overlapping manner. Msx1/Msx2 double-mutant mice displayed embryonic abdominal wall defects with disorganized muscle layers and connective tissues. These findings indicate that Msx1 and Msx2 play roles in concert during embryonic ventral abdominal wall formation.
Full-text · Article · May 2005 · The Anatomical Record Part A Discoveries in Molecular Cellular and Evolutionary Biology