Department of Biological Sciences, University of Massachusetts Lowell, Lowell, MA, USA.
Sci Rep. 2024 Aug 27;14(1):19944. doi: 10.1038/s41598-024-68608-z.
Modifications to highly conserved developmental gene regulatory networks are thought to underlie morphological diversification in evolution and contribute to human congenital malformations. Relationships between gene expression and morphology have been extensively investigated in the limb, where most of the evidence for alterations to gene regulation in development consists of pre-transcriptional mechanisms that affect expression levels, such as epigenetic alterations to regulatory sequences and changes to cis-regulatory elements. Here we report evidence that alternative splicing (AS), a post-transcriptional process that modifies and diversifies mRNA transcripts, is dynamic during limb development in two mammalian species. We evaluated AS patterns in mouse (Mus musculus) and opossum (Monodelphis domestica) across the three key limb developmental stages: the ridge, bud, and paddle. Our data show that splicing patterns are dynamic over developmental time and suggest differences between the two mammalian taxa. Additionally, multiple key limb development genes, including Fgf8, are differentially spliced across the three stages in both species, with expression levels of the conserved splice variants, Fgf8a and Fgf8b, changing across developmental time. Our data demonstrates that AS is a critical mediator of mRNA diversity in limb development and provides an additional mechanism for evolutionary tweaking of gene dosage.
人们认为，高度保守的发育基因调控网络的改变是进化中形态多样化的基础，并导致了人类先天畸形。在肢体中，已经广泛研究了基因表达和形态之间的关系，在肢体中，发育中基因调控改变的大多数证据都来自于影响表达水平的转录前机制，例如调节序列的表观遗传改变和顺式调控元件的变化。在这里，我们报告了证据表明，可变剪接（AS）是一种转录后过程，可以修饰和多样化 mRNA 转录本，在两种哺乳动物物种的肢体发育过程中是动态的。我们在三个关键的肢体发育阶段（脊、芽和桨）评估了小鼠（Mus musculus）和袋狸（Monodelphis domestica）的 AS 模式。我们的数据表明，剪接模式随发育时间而变化，并表明两种哺乳动物类群之间存在差异。此外，包括 Fgf8 在内的多个关键肢体发育基因在两个物种的三个阶段都存在差异剪接，保守剪接变体 Fgf8a 和 Fgf8b 的表达水平随发育时间而变化。我们的数据表明，AS 是肢体发育中 mRNA 多样性的关键介导者，并为基因剂量的进化微调提供了另一种机制。
