Fig. 5.

5-HT₆R rescue increases dendritic length. Primary striatal/cortical cocultures from 5-HT₆R KO pups were transfected on DIV7 with Map2B-RFP ± 70% empty vector or 55% EV + 15% WT-5-HT₆, 5-HT₆ ^406–411del, or 5-HT₆ ^D106A. On DIV10, cultures were fixed, immunostained for Arl13B and HA-tag, then imaged and analyzed. (A) Representative images of neurons transfected with different 5-HT₆ receptors and mutants. (B) Average number of dendritic branches. (C) Average dendritic length. (D) Average dendritic length of ciliated vs. unciliated neurons. (E) Average dendritic length of ciliated neurons with and without the receptor in cilia. Data measured from three to six neurons per coverslip (same cells and cultures as in Fig. 4) and pooled into a single data point. Three to six coverslips were analyzed across eight experiments. (B and C) (n coverslips, n = EV-31, WT-32,5-HT₆ ^406–411del-31, 5-HT₆ ^D106A-33), one-way ANOVA, Bonferroni post-hoc. (D) n coverslips = ciliated/unciliated, EV n = 30/20, WT n = 29/24, 5-HT₆ ^406–411del-29/22, 5-HT₆ ^D106A-30/22), two-way ANOVA, Bonferroni post-hoc. (E) n coverslips = cilia with receptor/cilia without receptor, EV n = 0/31, WT n = 27/26, 5-HT₆ ^406–411del-29/27, 5-HT₆ ^D106A-30/23). Post-hoc analysis, *P < 0.05; **P < 0.01 compared with EV (ciliated or cilia without receptor control), and ^$P < 0.05 compared with EV ciliated or EV receptor without cilia control.