Pax‐7 Immunoreactivity in the Post‐natal Chicken Central Nervous System

Abstract

In this immunocytochemical study on the constitutive expression of Pax-7 protein in the postnatal chicken brain, Pax-7 showed region and cell type specific expression. In the optic tectum, only cells in grey matter showed positive immunoreactivities (IRs), whereas those in the white matters did not show any IRs. In thalamic nuclei and several pontine nuclei, we also localized Pax-7 positive IRs. On the contrary, in the cerebellum, Pax-7 was mainly localized within the Bergmann glia, whereas Purkinje cells did not show any IRs. In double immunolabelling studies, most of the Pax-7 IRs did not originate from neuroglial cells such as oligodendrocytes, microglia or astrocytes, but from neurons, with the exception of Bergmann glia in the cerebellum. The presence of Pax-7 IRs in the adult chicken brain could suggest that Pax-7 might play a role in maintaining normal physiological function in some postnatal chicken brain cells.

Conserved localization of Pax6 and Pax7 transcripts in the brain of representatives of sarcopterygian vertebrates during development supports homologous brain regionalization

“…In adult chickens, Pax7 was found in neurons located mostly in the outer layers of the optic tectum (Shin et al, 2003). Also in chickens, the crucial role of Pax7 in tectal development was demonstrated because the ectopic Pax7 expression in the diencephalon was proved to induce the formation of an ectopic tectum (Matsunaga et al, 2000).…”

“…Interestingly, Pax6 and Pax7 are also expressed in adult brains in restricted and well-localized cell groups and regions (Walther and Gruss, 1991; Stoykova and Gruss, 1994; Kawakami et al, 1997; Shin et al, 2003; Thompson and Ziman, 2011; Duan et al, 2012), suggesting their involvement in the maintenance of distinct neuronal identity (Ninkovic et al, 2010), in physiological functions in mature neurons (Stoykova and Gruss, 1994; Shin et al, 2003), and as key regulators of a cell’s measured response to a dynamic environment (Blake et al, 2008). …”

Insight into the complex genetic network of tetraploid Atlantic salmon (Salmo salar L.): Description of multiple novel Pax-7 splice variants

“…In vivo Pax-7 is expressed in dorsal CNS progenitors (Renoncourt et al, 1998) and in specific neurones of the post-natal chicken brain as well as in the Bergmann glia of the cerebellum (Shin et al, 2003). In the mouse, Pax-7 −/− knockouts lack muscle satellite cells and show dramatically reduced growth, thus Pax-7 transcriptional activity may stimulate the specification of satellite cells .…”

Perplexing Pax: From puzzle to paradigm

“…Spleen, bone marrow Speculate tumor suppressor activity (Kaneko et al, 1998) (Stoykova and Gruss, 1994) Midbrain Superior collicular neurons Not specified (Thompson et al, 2004(Thompson et al, , 2007(Thompson et al, , 2008 Chicken Brain *Tectal neurons *Nuclei of Thalamus/Pons/ Midbrain Speculate maintenance of normal physiology (Shin et al, 2003) Cerebellar Bergmann glia…”

“…Pax expression continues in the adult, in both stem/progenitor cell populations and, intriguingly, in mature cells (Seale et al, 2000;Shin et al, 2003;Thompson et al, 2004Thompson et al, , 2007Thompson et al, , 2008Maekawa et al, 2005;Thomas et al, 2007;Fedtsova et al, 2008). The reason for persistent expression in mature cells, particularly in the cen-tral nervous system (CNS), has perplexed us and instigated our quest to better define the role of Pax genes.…”