Title: Intron-targeted mutagenesis reveals roles for Dscam1 RNA pairing architecture-driven splicing bias in neuronal wiring 

Weiling Hong, Jian Zhang, Haiyang Dong, Yang Shi, Hongru Ma, Fengyan Zhou, Bingbing Xu, Ying Fu, Shixin Zhang, Shouqing Hou, Guo Li, Yandan Wu, Shuo Chen, Xiaohua Zhu, Wendong You, Feng Shi, Xiaofeng Yang, Zhefeng Gong, Jianhua Huang, Yongfeng Jin

Summary

Drosophila melanogaster Down syndrome cell adhesion molecule (Dscam1) can generate 38,016 different isoforms through largely stochastic, yet highly biased, alternative splicing. These isoforms are required for nervous functions. However, the functional significance of splicing bias remains unknown. Here, we provide evidence that Dscam1 splicing bias is required for mushroom body (MB) axonal wiring. We generate mutant flies with normal overall protein levels and an identical number but global changes in exon 4 and 9 isoform bias (DscamΔ4D−/− and DscamΔ9D−/−), respectively. In contrast to DscamΔ4D−/−, DscamΔ9D−/− exhibits remarkable MB defects, suggesting a variable domain-specific requirement for isoform bias. Importantly, changes in isoform bias cause axonal defects but do not influence the self-avoidance of axonal branches. We conclude that, in contrast to the isoform number that provides the molecular basis for neurite self-avoidance, isoform bias may play a role in MB axonal wiring by influencing non-repulsive signaling.

Link:  https://doi.org/10.1016/j.celrep.2021.109373

More: Role of Dscam1 alternative splicing bias in neuronal wiring