Birth and death of cells in limb development: A mapping study

Abstract

Cell death and cell proliferation are basic cellular processes that need to be precisely controlled during embryonic development. The developing vertebrate limb illustrates particularly well how correct morphogenesis depends on the appropriate spatial and temporal balance between cell death and cell proliferation. Precise knowledge of the patterns of cell proliferation and cell death during limb development is required to understand how their modifications may contribute to the generation of the great diversity of limb phenotypes that result from spontaneous mutations or induced genetic manipulations. We have performed a comprehensive analysis of the patterns of cell death, assayed by terminal deoxynucleotidyl transferase-mediated deoxyuridinetriphosphate nick end-labeling (TUNEL), and cell proliferation, assayed by anti-phosphorylated histone H3 immunohistochemistry, in consecutive sections of forelimbs and hindlimbs covering an extensive period of chick and mouse limb development. Our results confirm and expand previous reports and show common and specific areas of cell death for each species. Mitotic cells were found scattered in a uniform distribution across the early limb bud, with the exception of the areas of cell death in which mitotic cells were scarce. At later stages, mitotic cells were seen more abundantly in the digital tips. The aim of the present study was to satisfy the need for organized data sets describing these processes, which will allow the side-by-side comparison between the two major model organisms of limb development, i.e., the mouse and the chick.

The incomplete inactivation of Fgf8 in the limb ectoderm affects the morphogenesis of the anterior autopod through BMP‐mediated cell death

“…In E13.5, normal limb buds, pH 3-positive cells were scarce in the interdigits and in the condensed chondrogenic elements ( Fig. 5A; Fernandez-Teran et al, 2006). Interestingly, in the mutant limb the abnormal area of cell death at the base of digits 2/3 was devoid of mitotic cells (Fig.…”

“…To investigate the cause of this defect, we analyzed cell death in limb buds of mutant and normal littermates by TUNEL during the time at which the digits are specified (from E11.5 to E13.5). The distribution of apoptotic cells in mutant limb buds at E11.5 and E12.5 was as described (Fernandez-Teran et al, 2006) for normal limb buds (data not shown). However, at E13.5 an abnormal area of cell death was detected at the base of digits 2/3 in mutant forelimb buds (arrow in Fig.…”

Cathepsin D gene expression outlines the areas of physiological cell death during embryonic development

“…The limb bud was chosen because it has been one of the embryonic structures studied in more detail in relation with PCD (see Zuzarte-Luis and Hurle, 2002;Fernandez-Teran et al, 2006). We previously reported that cathepsin B and D expression appeared very precise markers for the anterior and posterior areas of cell death (ANZ and PNZ) and also for the areas of interdigital cell death (INZ; ZuzarteLuis et al, 2007).…”

Regulative patterning in limb bud transplants is induced by distalizing activity of apical ectodermal ridge signals on host limb cells

“…Despite its originality, this approach had a major disadvantage: it assumed uniform expansion along the P-D axis. It is now known that this is not the case, at least for the developing mouse limb (Boehm et al, 2010), while less clear evidence exists for the chicken limb (Hornbruch and Wolpert, 1970;Fernandez-Teran et al, 2006). The second problem is the limited ability to recognize which elements are formed from the graft and which from the host.…”