Centrosome defects cause microcephaly by activating the 53BP1‐USP28‐TP53 mitotic surveillance pathway

A

Representative whole mount images of WT, Sas4^cKO, Sas4^cKO;Trp53bp1 ^−/−, Sas4^cKO;Usp28^cKO animals at P14. Arrows indicate the cerebellar hypoplasia resulting from the lack of primary cilia. Scale bar = 0.2 cm.

B

Telencephalon area of P14 brains of the indicated genotypes. WT littermates N = 8, Sas4^cKO N = 7, Sas4^cKO;Trp53bp1 ^−/− N = 6, Sas4^cKO;Usp28^cKO N = 10, Sas4^cKO;Trp53 ^−/− N = 5; one‐way ANOVA with post hoc analysis. WT and Sas4^cKO data are from Fig 1D and shown alongside for comparison. Black circles represent Nestin‐Cre⁺ animals.

C

Cortical thickness of P14 brains of the indicated genotypes. WT littermates N = 4, Sas4^cKO N = 4, Sas4^cKO;Trp53bp1 ^−/− N = 4, Sas4^cKO;Usp28^cKO N = 4, Sas4^cKO;Trp53 ^−/− N = 4; one‐way ANOVA with post hoc analysis. WT and Sas4^cKO data are from Fig EV1D and shown alongside for comparison. Black circles represent Nestin‐Cre⁺ animals.

D

Representative whole mount images of WT, Cep63^T/T, Cep63^T/T;Trp53bp1 ^−/−, Cep63^T/T;Usp28 ^−/− animals at P60. Scale bar = 0.2 cm.

E

Telencephalon area of P60 brains of the indicated genotypes. WT littermates N = 4, Cep63^T/T N = 7, Cep63^T/T;Trp53bp1 ^−/− N = 6, Cep63^T/T;Usp28 ^−/− N = 5; one‐way ANOVA with post hoc analysis. WT and Cep63^T/T data are from Fig 1B and shown alongside for comparison.

F

Cortical thickness of P60 brains of the indicated genotypes. WT littermates N = 4, Cep63^T/T N = 5, Cep63^T/T;Trp53bp1 ^−/− N = 3, Cep63^T/T;Usp28 ^−/− N = 3; one‐way ANOVA with post hoc analysis. WT and Cep63^T/T data are from Fig EV1B and shown alongside for comparison.

G

Body weight of P7 animals of the indicated genotypes. WT littermates N = 18, Cep63^T/T N = 16, Cep63^T/T;Trp53bp1 ^−/− N = 2, Cep63^T/T;Usp28 ^−/− N = 10; one‐way ANOVA with post hoc analysis.

H

Quantification of total number of cells within a 500 μm‐width column of cortices at P60. WT littermates N = 4, Cep63^T/T N = 4, Cep63^T/T;Trp53bp1 ^−/− N = 4, Cep63^T/T;Usp28 ^−/− N = 3; one‐way ANOVA with post hoc analysis.

I, J

Quantification of the number of cells in the (I) superficial layer (CUX1⁺) and (J) deep layer (CTIP2⁺) within a 500 μm‐width column of P60 cortices. WT littermates N = 3, Cep63^T/T N = 4, Cep63^T/T;Trp53bp1 ^−/− N = 4, Cep63^T/T;Usp28 ^−/− N = 3; one‐way ANOVA with post hoc analysis.

K

P60 cortices of indicated genotypes stained with antibodies against the deep layer marker CTIP2 (green), superficial layer marker CUX1 (red) and DAPI (blue). Scale bar = 200 μm.

Figure 3. Centrosome defects reduce brain size through activation of the mitotic surveillance pathway.