PLOS Genet 2019 Dec 26; 15(12):e1008554
The mammalian Pcdhg gene cluster encodes a family of 22 cell adhesion molecules, the gamma-Protocadherins (γ-Pcdhs), critical for neuronal survival and neural circuit formation. The extent to which isoform diversity-a γ-Pcdh hallmark-is required for their functions remains unclear. We used a CRISPR/Cas9 approach to reduce isoform diversity, targeting each Pcdhg variable exon with pooled sgRNAs to generate an allelic series of 26 mouse lines with 1 to 21 isoforms disrupted via discrete indels at guide sites and/or larger deletions/rearrangements. Analysis of 5 mutant lines indicates that postnatal viability and neuronal survival do not require isoform diversity. Surprisingly, given reports that it might not independently engage in trans-interactions, we find that γC4, encoded by Pcdhgc4, is the only critical isoform. Because the human orthologue is the only PCDHG gene constrained in humans, our results indicate a conserved γC4 function that likely involves distinct molecular mechanisms.
Garrett, Andrew M.; Bosch, Peter J; Steffen, David M; Fuller, Leah C; Marcucci, Charles G; Koch, Alexis A; Bais, Preeti; Weiner, Joshua A; and Burgess, Robert W., "CRISPR/Cas9 interrogation of the mouse Pcdhg gene cluster reveals a crucial isoform-specific role for Pcdhgc4." (2019). Faculty Research 2019. 282.