Long introns delay transcriptional time


In a negative feedback loop, does intron lenght affects gene expression? Yan Swinburne and colleagues (Harward) answered this question by engineering a gene network and modifying only intron length between clonal variants. What they observed was such network (with delayed autoinhibition) exhibiting pulses of reporter expression that were correlating with intron length. A successive simulation with mathematical models suggested that fluorescence bursting (Venus fast-maturing variant of yellow fluorescent protein) accumulated during transcription elongation.

Note in the construct diagram the presence of PEST and ARE used to destabilize both protein and mRNA: destabilization is fundamental to limit reporter accumulation and so to gain time-resolution. (Swinburne et al, Genes and Development 2008)

The delay of transcriptional machine by introns may be important in many contexts (somitogenesis during development, NF-kb patterns). Undoubtedly, this work further evidences that reporter genes are instrumental to the goals of system biology.

I. A. Swinburne, D. G. Miguez, D. Landgraf, P. A. Silver (2008). Intron length increases oscillatory periods of gene expression in animal cells Genes & Development, 22 (17), 2342-2346 DOI: 10.1101/gad.1696108