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. Author manuscript; available in PMC: 2009 May 5.
Published in final edited form as: Curr Opin Neurobiol. 2008 Jun 2;18(1):90–100. doi: 10.1016/j.conb.2008.05.011

Figure 4. Selective deletion of COUP-TFI from cortex results in massive expansion of frontal/motor areas and posterior compression of primary sensory areas.

Figure 4

Findings from [38] showing a prominent role for COUP-TFI in arealization. (A,B) Serotonin (5HT) immunostaining on tangential sections through layer IV of flattened cortices of P7 control (COUP-TFIfl/+) and conditional mutant (fl/fl; Emx1-Cre) cortices. Anterior is to left, and medial to the top. (A) Serotonin staining reveals primary sensory areas, including primary somatosensory (S1), visual (V1) and auditory (A1) areas, by marking area-specific TCA axon terminations. (B) In COUP-TFI fl/fl; Emx1-Cre conditional mutant brains, the primary sensory areas are much smaller than in controls and are compressed to ectopic positions at the posterior pole of the cortical hemisphere. The barrelfield of the ectopic S1 retains its characteristic patterning but is substantially reduced in size and caudally shifted, while a reduced V1 is located medial and a reduced A1 lateral to the miniature S1 barrelfield. (C,D) In situ hybridization for Cad8 on whole mounts of P7 wild-type (+/+; Emx1-Cre) and homozygous conditional mutant (COUP-TFIfl/fl; Emx1-Cre) brains uniquely marks the frontal/motor areas (F/M). The F/M areas substantially expand following selective deletion of COUP-TFI from cortex. The reduced ectopic primary sensory areas (V1, S1) can be identified by small domains of diminished cad8 expression in posterior cortex. (E–J) Serotonin (5HT) immunostaining (E,F) MDGA1 (G,H) and RORβ (I,J) in situ hybridization on serial sagittal sections of P7 control (COUP-TFIfl/+) and conditional mutant (fl/fl; Emx1-Cre) cortices. Anterior is to the left, dorsal to the top. Serotonin immunostaining reveals area-specific TCA terminations in layer 4 of S1 and V1. In conditional mutant cortex, both S1 and V1 are reduced in size and are ectopically positioned at the posterior pole of the cortical hemisphere (F). (G,H) MDGA1 selectively marks layers 4 and 6 of S1, and layer 2/3 more broadly in cortex. The S1 specific expression of MDGA1 in layers 4 and 6 confirms the reduced size and posterior shift of S1 in the COUP-TFI deficient cortex, and that these changes occur in parallel across cortical layers. (I,J) RORβ is expressed predominantly in layer 4 of the primary sensory areas (e.g. S1, V1) in wild type cortex (I). RORβ expression in the COUP-TFI deficient cortex is altered to parallel the changes in area patterning in mutant cortex (J). The majority of the cortex in the conditional mutants, including all of the neocortex anterior to the reduced, caudally-shifted primary sensory areas, exhibit serotonin staining and expression of MDGA1 and RORβ that are characteristic of wild type Frontal/Motor cortex (F/M). Scale bars: 1mm. Figure is modified from [38].