Differential Gene Expression between Sensory Neocortical Areas: Potential Roles for Ten_m3 and Bcl6 in Patterning Visual and Somatosensory Pathways

Abstract

Adult neocortical areas are characterized by marked differences in cytoarchitecture and connectivity that underlie their functional roles. The molecular determinants of these differences are largely unknown. We performed a microarray analysis to identify molecules that define the somatosensory and visual areas during the time when afferent and efferent projections are forming. We identified 122 molecules that are differentially expressed between the regions and confirmed by quantitative polymerase chain reaction 95% of the 20 genes tested. Two genes were chosen for further investigation: Bcl6 and Ten_m3. Bcl6 was highly expressed in the superficial cortical plate corresponding to developing layer IV of somatosensory cortex at postnatal day (P) 0. This had diminished by P3, but strong expression was found in layer V pyramidal cells by P7 and was maintained until adulthood. Retrograde tracing showed that Bcl6 is expressed in corticospinal neurons. Ten_m3 was expressed in a graded pattern within layer V of caudal cortex that corresponds well with visual cortex. Retrograde tracing and immunostaining showed that Ten_m3 is highly expressed along axonal tracts of projection neurons of the developing visual pathway. Overexpression demonstrated that Ten_m3 promotes homophilic adhesion and neurite outgrowth in vivo. This suggests an important role for Ten_m3 in the development of the visual pathway.

Tbr1 regulates regional and laminar identity of postmitotic neurons in developing neocortex

“…Previous studies have shown that Tbr1 exhibits high rostral and low caudal expression in developing neocortex (12)(13)(14). This suggests that Tbr1 may contribute to the implementation of frontal cortex identity.…”

“…Because anatomical landmarks of cortical areas (e.g., somatosensory barrels) are not developed on P0.5, we assessed regional identity using molecular expression patterns (12,13). Previous studies have described several regional markers in embryonic and neonatal cortex, such as Bcl6 rostrally and Odz3 caudally (14,24,25). To find additional regional markers, we mined online databases (26)(27)(28), previous publications, and our microarray data (Dataset S1 and Dataset S2).…”

“…Previously, we have shown that Tbr1 is necessary for the differentiation of preplate and layer 6 neurons (11). Whereas Tbr1 is expressed at the highest levels in developing frontal cortex (12)(13)(14), we hypothesized that Tbr1 might implement frontal identity. This hypothesis accords with evidence that Tbr1 is expressed downstream of Pax6 through a TF cascade from Pax6 + radial progenitors to Tbr1 + postmitotic projection neurons (15)(16)(17)(18).…”

Caenorhabditis elegansTeneurin,ten-1, Is Required for Gonadal and Pharyngeal Basement Membrane Integrity and Acts Redundantly with Integrinina-1and Dystroglycandgn-1

“…The intracellular domain contains proline-rich stretches and putative tyrosine phosphorylation sites but is less conserved than the extracellular part and cannot be aligned in a linear way between the phyla. Teneurins are thought to interact in a homophilic manner (Oohashi et al, 1999;Rubin et al, 2002;Bagutti et al, 2003;Leamey et al, 2008) and to date, no other ligand has been identified.…”

Quantitative Analysis in Impression for Trademarks, Symbols and Logotypes of Corporations in Terms of Familiarity and Design Category

“…The field of graphic design lies over manifold kind [25] (v., app.). Widely ranged visual perception of human, there is a genetic study [26]. Graphic design is defined as a consciousness that consists of both thought and art.…”