Which option correctly describes the transcription factor markers for cortical layers?

Which option correctly describes the transcription factor markers for cortical layers?

• A. Upper layers: CUX1/CUX2; Deep layers: CTIP2 (BCL11B) and TBR1.
• B. Upper layers: CTIP2 and TBR1; Deep layers: CUX1/CUX2.
• C. Upper layers: PAX6; Deep layers: SOX2.
• D. Upper layers: SOX5; Deep layers: CUX2.

Answer: (C)

In the cortex, neurons acquire layer-specific identities reflected by transcription factors. Upper-layer neurons (layers II/III) characteristically express CUX1 and CUX2, while deep-layer neurons (layers V/VI) express CTIP2 (BCL11B) and TBR1. PAX6 and SOX2, on the other hand, are markers of progenitor cells—PAX6 for radial glia/early progenitors and SOX2 for neural stem cells—not mature cortical layer neurons. So the description that pairs CUX1/2 with upper layers and CTIP2/TBR1 with deep layers accurately reflects the established layer-specific neuronal identity, whereas PAX6 and SOX2 describe progenitor populations rather than the mature cortical layers.

In the cortex, neurons acquire layer-specific identities reflected by transcription factors. Upper-layer neurons (layers II/III) characteristically express CUX1 and CUX2, while deep-layer neurons (layers V/VI) express CTIP2 (BCL11B) and TBR1. PAX6 and SOX2, on the other hand, are markers of progenitor cells—PAX6 for radial glia/early progenitors and SOX2 for neural stem cells—not mature cortical layer neurons. So the description that pairs CUX1/2 with upper layers and CTIP2/TBR1 with deep layers accurately reflects the established layer-specific neuronal identity, whereas PAX6 and SOX2 describe progenitor populations rather than the mature cortical layers.