Programmed Cell Death duringXenopusDevelopment: A Spatio-temporal Analysis

Abstract

Programmed cell death (PCD) is an integral part of many developmental processes. In vertebrates little is yet known on the patterns of PCD and its role during the early phases of development, when embryonic tissue layers migrate and pattern formation takes place. We describe the spatio-temporal patterns of cell death during early Xenopus development, from fertilization to the tadpole stage (stage 35/36). Cell death was analyzed by a whole-mount in situ DNA end-labeling technique (the TUNEL protocol), as well as by serial sections of paraffin-embedded TUNEL-stained embryos. The first cell death was detected during gastrulation, and as development progressed followed highly dynamic and reproducible patterns, strongly suggesting it is an important component of development at these stages. The detection of PCD during neural induction, neural plate patterning, and later during the development of the nervous system highlights the role of PCD throughout neurogenesis. Additionally, high levels of cell death were detected in the developing tail and sensory organs. This is the first detailed description of PCD throughout early development of a vertebrate, and provides the basis for further studies on its role in the patterning and morphogenesis of the embryo.

Hyaluronan is required for cranial neural crest cells migration and craniofacial development

“…TUNEL assay on whole mount embryos was performed as described by Hensey and Gautier (1998). Whole mount processed embryos were then vibratome sectioned.…”

Xenopus hairy2 functions in neural crest formation by maintaining cells in a mitotic and undifferentiated state

“…TUNEL staining was performed as previously described (Hensey and Gautier 1998). In brief, fixed embryos were rehydrated in PBS containing 0.1% Tween 20, and washed with terminal deoxynucleotidyl transferase (TdT) buffer (Gibco) for 30 min.…”

Xeya3 regulates survival and proliferation of neural progenitor cells within the anterior neural plate of Xenopus embryos

“…Apoptotic cells were detected using the TUNEL assay (Hensey and Gautier, 1998). Mitotic cells were identified by the detection of phosphorylated histone H3 in neurulae and early tail bud stages as described (Saka and Smith, 2001).…”