Expression of the neural cell adhesion molecule and polysialic acid during early mouse embryogenesis

Abstract

The expression of the neural cell adhesion molecule (N‐CAM) and α 2–8 linked polysialic acid (PSA), which is believed to be predominantly expressed on N‐CAM, was investigated during early embryonic development of the mouse (embryonic days 7.5 to 10.0). By immunocytochemistry, in tissue sections, N‐CAM and PSA were not detectable at embryonic day 7.5 but were expressed in the prominent body regions such as somites, unsegmented mesoderm, developing heart, and neuroectoderm at embryonic day 8.0 N‐CAM and PSA immunoreactivities were always predominantly associated with the plasma membrane. No tissue could be detected which was positive for PSA but negative for N‐CAM. In Western blot analysis of whole embryos, by contrast, only the lightly sialylated and PSA‐negative 180 and 140 kD isoforms of N‐CAM were present at embryonic day 8.0 and strong expression of PSA‐bearing, heavily sialylated N‐CAM was not detectable before embryonic day 10.0. In Western blot analysis of N‐CAM immunoaffinity purified from whole embryos and digested with neuraminidase as well as in Northern blot analysis, the 120 kD isoform of N‐CAM or its corresponding mRNA were not expressed in detectable amounts during the time period investigated. © 1994 Wiley‐Liss, Inc.

ENC-1: A Novel MammalianKelch-Related Gene Specifically Expressed in the Nervous System Encodes an Actin-Binding Protein

“…Others genes recognized to be expressed in early precursors of the developing vertebrate NS, including Otx-2, XlHbox 6, XIPOU 2, and N-CAM, are distinguishable from ENC-1 in that their expression can also be detected in a variety of different lineages (Kintner and Melton, 1987;Wright et al, 1990;Simeone et al, 1992Simeone et al, , 1993Pannese et al, 1995;Witta et al, 1995). For example, N-CAM, which is the most commonly used general marker of neural induction, is first detected at E8.0, and it is also expressed in other body regions such as somites, unsegmented mesoderm, and developing heart (Probstmeier et al, 1994). In contrast, other genes such as type II ␤-tubulin and midsize neurofilament, which are specifically detected within neural structures, are not expressed before NS differentiation is morphologically recognizable.…”

Targeted mutation of Ncam to produce a secreted molecule results in a dominant embryonic lethality.

“…Fetuses were dissected and analyzed between embryonic day (E) 8.5 and E10.5, the time at which NCAM begins to be expressed (12). Approximately 6% of the embryos were found to be growth delayed or undergoing resorption (Table 1), and this class of embryos contained greater than 90% ES cell contribution as shown by Southern blot analysis and scanning densitometry (data not shown).…”

A role for neural cell adhesion molecule in the formation of the avian inner ear

“…Both the tailbud and otic primordium have low levels of sialidation at the time they are susceptible to inhibition by anti-N-CAM, based on minimal localization of antibody against polysialic acid. Thus, the antibody may mimic polysialidation, which correlates in some organs with the end of morphogenetic processes (Probstmeier et al, 1994), although not in pronephric duct migration (Bellairs et al, 1995).…”