Roles of Pax-genes in developing and adult brain as suggested by expression patterns

Abstract

We have examined the transcript distribution of six members of the murine paired box-containing gene family (Pax-gene family) in midgestation embryo and adult brain using in situ hybridization analysis. The expression domains of several Pax-genes in the embryo brain were found to correspond with anatomical boundaries that coincide with neuromere landmarks and therefore respect former neuromere territories in the forebrain. The results are consistent with the concept of brain segmentation and suggest a role for Pax-genes in the brain regionalization. In the adult brain the expression of Pax-genes was observed in discreet areas, with a caudal to rostral restriction in the number of the expressed genes. In general the distribution of transcripts along the anterior-posterior axis was similar to that found in midgestation embryo brain, suggesting a role for Pax-genes in the commitment of the precursor cells to different neuronal cell fates and in the maintenance of specific brain cell subtypes. In the cerebellar cortex, the granular cell layer was found to express high levels of the Pax-6 gene, while putative Bergmann glia and cells surrounding the Purkinje cells contained Pax-3 transcripts. The main adult brain structures that expressed distinct Pax-mRNAs were the periglomerular and granular cell layer of olfactory bulb, nuclei of the septum, amygdala, and isthmus, which suggests a role for the Pax-gene family in the specification of the subcortical domains of the evolutionary old limbic system.

Apoptosome inactivation rescues proneural and neural cells from neurodegeneration

“…(b) Analysis of differentiation markers from e14 wt and Apaf1 À/À littermate embryos. nestin, delta1, notch1 mRNA levels were revealed by in situ mRNA hybridization as previously described (Stoykova and Gruss, 1994) …”

“…In situ hybridization on paraffin-embedded sections was also performed as previously described. 42 After staining, the embryos were embedded in paraffin and sectioned. Photographs were taken using a Zeiss-Axioskop microscope.…”

Gsh‐1: A novel murine homeobox gene expressed in the central nervous system

“…In contrast, several of the dispersed homeobox genes show discrete patterns of transcription in more anterior regions of the developing brain. These dispersed homeobox genes may function in a combinatorial fashion to determine pattern formation in the neuromeric segmentation of the brain similar to the clustered Hox genes along the neural tube Stoykova and Gruss, 1994). The Dlx family members, for example, are expressed in intricate patterns in the forebrain, as well as in limbs, developing branchial arches, face, and eyes (Robinson et al, 1991;Porteus et al, 1991Price et al, 1991;Dolle et al, 1992;Bulfone et al, 1993).…”

Pax2 modulates proliferation during specification of the otic and epibranchial placodes

“…Pax2 groups with Pax5 and Pax8, and in many regions of the embryo either two or all three of the Pax2/5/8 sub-family, are co-regulated (Krelova et al, 2002). In most vertebrates, the mid-hindbrain boundary expresses all three genes, although the kidney and inner ear primordia only express Pax2 and Pax8 (Plachov et al, 1990;Stoykova and Gruss, 1994;Lun and Brand, 1998;Pfeffer et al, 1998;Funahashi et al, 1999;Kozmik et al, 1999;Bouchard et al, 2002;Krelova et al, 2002;Hans et al, 2004), with Pax5 not present in these tissues (Funahashi et al, 1999;Kwak et al, 2006). The overlap between Pax2 and Pax8 in the PPA has confounded functional characterization of this Pax subfamily due to their presumed redundancy.…”