Timing is everything: advances in quantifying splicing kinetics.

Techniques to study splicing kinetics include metabolic labeling time courses, 3′ splice site-RNA polymerase II distance-based measurements, and microscopy-based methods. The global median splicing time is of the order of minutes in many organisms, including yeast, Drosophila , and humans. Many instances of splicing events occurring on the order of seconds have also been observed. Single intron excision kinetics are highly variable. Many molecular features are associated with splicing kinetics, including intron length, the distance of an intron from its respective gene boundaries, and whether a splicing event is alternative or constitutive. Splicing is a highly regulated process critical for proper pre-mRNA maturation and the maintenance of a healthy cellular environment. Splicing events are impacted by ongoing transcription, neighboring splicing events, and cis and trans regulatory factors on the respective pre-mRNA transcript. Within this complex regulatory environment, splicing kinetics have the potential to influence splicing outcomes but have historically been challenging to study in vivo. In this review, we highlight recent technological advancements that have enabled measurements of global splicing kinetics and of the variability of splicing kinetics at single introns. We demonstrate how identifying features that are correlated with splicing kinetics has increased our ability to form potential models for how splicing kinetics may be regulated in vivo. [ABSTRACT FROM AUTHOR]