In contrast, cortical layering is unaffected in both Bhlhb5 and Prdm8 knockout mice ( Figure S3). Thus, both Bhlhb5 Alectinib order and Prdm8 are required for

the correct targeting of projection neurons of the dorsal telencephalon. In addition to showing common axonal targeting defects, we found that Bhlhb5 and Prdm8 mutant mice have similar behavioral abnormalities. For example, both mutants show abnormal itching behavior that results in the formation of skin lesions, which is observed in 100% of Bhlhb5 mutant mice and ∼75% of Prdm8 mutant mice ( Figure 2C). Furthermore, ∼5% of mice lacking either Bhlhb5 or Prdm8 occasionally display an unusual movement in which they walk on their forepaws ( Figure 2D).

The remarkable similarity of the cellular and behavioral phenotypes observed in mice lacking either Bhlhb5 or Prdm8 strongly suggests that these factors function together, possibly as obligate partners of the same transcriptional repressor complex. If Bhlhb5 and Prdm8 form a protein complex that represses transcription, we would expect Bhlhb5 and Prdm8 to (1) be expressed in the same subsets of neurons, (2) inhibit the same target genes, and (3) bind together to the www.selleckchem.com/products/VX-809.html same regulatory elements in DNA. Thus, we set out to test each of these possibilities. We began by generating antibodies to Prdm8 (Figure S3) to characterize its expression pattern. At the subcellular level, both Bhlhb5 and Prdm8 show a similar distribution in the nucleus (Figures 3A and 3B). Moreover, analysis of sections from wild-type mice at a variety of embryonic and early postnatal ages revealed that Bhlhb5 and Prdm8 show a high degree of colocalization in select subpopulations of differentiating neurons. For instance, Bhlhb5 and Prdm8 are both Bay 11-7085 expressed in the intermediate zone and the cortical plate of dorsal telencephalon from E13.5–E17.5 (Figure S5A).

By P0, both factors are highly expressed in superficial layers of the cortex (Figure 3B). In other regions of the nervous system (where Bhlhb5 and Prdm8 are expressed more sparsely) the coexpression of these two proteins is even more apparent; Bhlhb5 and Prdm8 clearly mark a shared subset of neurons in the diencephalon (Figure 3B, inset ii), the brainstem (Figure S5B) and the spinal cord (Ross et al., 2010). This coexpression in specific populations of neurons suggests that Bhlhb5 and Prdm8 might work together to regulate common aspects of neuronal differentiation. Next, we investigated whether the same genes are misexpressed in Bhlhb5−/− and Prdm8−/− mice. To obtain an unbiased view, we independently determined the gene expression profiles of each mutant, analyzing mRNA expression in the dorsal telencephalon of mice.