Morphological Features of Tail Bud Development in Truncate Mouse Mutants

Stem cells and stroke-how glowing neurons illuminate new paths

A reliable method of cell tracing is essential in evaluating potential therapeutic procedures based on stem cell transplantation. Here we present data collected using neural stem cells isolated from a transgenic mouse line Thy1-YFP. When transplanted into a stroke affected brain these cells give rise to neurons that express a fluorescent signal which can be used for their detection and tracing. Observed processes were compared with those taking place during normal embryonic neurogenesis as well as during in vitro differentiation. Since the same neurogenic patterns were observed, we confirm that neural stem cell transplantation fits well into the paradigm of neuronal birth and differentiation.

The effect of vitamin A deficiency during pregnancy on anorectal malformations

OBJECTIVE

The aim of this study was to study the effect of vitamin A deficiency (VAD) on the embryological development of anorectal malformations (ARMs) and the enteric nervous system.

MATERIALS AND METHODS

Female Sprague-Dawley rats were divided into 3 groups: VAD group, normal group (negative control), and ethylene thiourea (ETU) group (positive control) with a normal diet. On day 20 of pregnancy, cesarean section was performed on all rats. The incidence of ARMs in the fetal rats and Protein gene product 9.5 (PGP9.5) and S-100 protein expression by immunohistochemistry were determined.

RESULTS

The incidence of ARMs in VAD and ETU groups was 64.8% (59/91) and 45.9% (61/133), respectively (P > .05). Anorectal malformations were not found in the normal group. Protein gene product 9.5 and S-100 protein expression in the non-ARM rectums of the VAD group was lower than the ETU (P = .0156 vs P = .0105) and normal groups (P = .0091 vs P = .0024). There was no significant difference in PGP9.5 and S-100 protein expression between ETU and normal groups. In the ARM rectums, PGP9.5 and S-100 protein expression in the VAD group was lower than the ETU group (P < .0001). Protein gene product 9.5 and S-100 protein expression was also lower in ARM than non-ARM rectums in the VAD and ETU groups (P < .0001, P = .0203, and P = .0122, respectively).

CONCLUSION

Vitamin A deficiency during pregnancy may result in the embryological development of ARMs. Enteric nervous system development may be related to ARMs.

Semi-thin sections of epoxy resin-embedded mouse embryos in morphological analysis of whole mount in situ RNA hybridization

Descriptive morphological studies are often combined with gene expression pattern analyses. Unembedded vibratome or cryotome sections are compatible with in situ RNA hybridization, but spatial resolution is rather low for precise microscopic studies necessary in embryology. Therefore, use of plastic embedding media, which allow semi-thin and ultra-thin sectioning for light and electron microscopy, could be an important advantage. This work suggested a new approach based on the whole mount hybridization of mouse embryos and subsequent epoxy resin embedding. Epoxy resin allowed serial sectioning of semi-thin sections with preserved in situ RNA hybridization signal, which was a necessary prerequisite for precise morphological analysis of embryo development.

PCR-based identification of short deletion/insertions and single nucleotide substitutions in genotyping of splotch (Pax3sp) and truncate (Nototc) mouse mutants

Splotch (Pax3(sp)) and truncate (Noto(tc)) are spontaneously arisen mouse mutants with disturbed embryo development. Splotch carries a Pax3 mutation and it is characterized by the neural tube defect. Corresponding mutation in human causes Waardenburg syndrome. Truncate is Noto mutant with disturbed development of the caudal notochord. In order to establish easy genotyping procedure of these mutations, it was tested whether simple PCRs with single primer pairs could be used for this purpose. As it was necessary to differentiate sequence variants on the scale of one to several nucleotides, the approach referred to as "3' variable primer ends" was applied. The method was based on the presence of discriminating nucleotides at the 3' end of the primer sequence. This approach was successfully applied in genotyping adult mice and embryos of splotch with a 6 bp deletion/insertion and truncate with a single nucleotide substitution. Described genotyping approach facilitates recognizing of these mutations and it could be in general used for detection of sequence differences in one to several nucleotides.