Transcription profiling by high throughput sequencing of liver and brain during mouse organ development

The genetic code is an abstraction of how mRNA codons and tRNA anticodons molecularly interact during protein synthesis; the stability and regulation of this interaction remains largely unexplored. Here, we quantitatively characterized the expression of mRNA and tRNA genes across developing mouse tissues. Substantial fractions of both gene sets dynamically change expression from early organogenesis to adult tissues. mRNA codon pools are highly stable over development and reflect the genomic background; in contrast, changes in transcription at specific tRNA genes are coordinated across anticodon families to produce a stable isoacceptor output. During development, the pools of mRNA codons and tRNA anticodons are invariant and highly correlated, revealing a stable molecular interaction interlocking transcription and translation.遗传密码（genetic code）是对蛋白质合成过程中，信使RNA（messenger RNA，mRNA）密码子与转运RNA（transfer RNA，tRNA）反密码子分子互作机制的抽象概括；目前，该互作的稳定性与调控机制仍在很大程度上未被探明。本研究对发育进程中小鼠各组织内的mRNA与tRNA基因表达水平开展了定量表征。两类基因集合中均有相当比例的成员，从早期器官发生阶段到成体组织期间，其表达水平均发生动态变化。mRNA密码子池在整个发育过程中高度稳定，且可反映基因组背景特征；与之相对，特定tRNA基因的转录变化会在反密码子家族间协同调控，以维持同功tRNA池的稳定产出。在发育过程中，mRNA密码子池与tRNA反密码子池始终保持恒定且高度相关，这揭示了一种将转录与翻译紧密联动的稳定分子互作机制。