Eukaryotic gene expression is remarkable: from limited genetic material, it creates various proteomes and cell types. To do so, genes are transcribed into pre-mRNAs that undergo processing including splicing, the mechanism of exon/intron retention or excision, to produce mature mRNAs. A single pre-mRNA can be spliced in different ways thereby diversifying transcript isoforms and proteins. This mechanism termed alternative splicing contributes to the diversity of cell and tissue identities in complex organisms. Conversely, aberrant splicing leads to severe pathologies such as neuromuscular disorders and cancers. However, realising how such transcriptional and splicing programs are coordinated is still a challenge in Biology.
Transcription factors (TFs) are the key players in gene expression by triggering precise spatial-temporal transcriptional programs. If most TFs act at the DNA regulatory layer, some TFs can bind RNA and modulate mRNA splicing. Yet, the mechanistic clues underlying TF function in alternative splicing remain elusive. Solving this issue will provide unique entry points to understand the mechanisms orchestrating cell and tissue diversity in animals and their aberrant regulation in diseases.
To address this central issue in gene regulation, we use the Hox TF as a model based on our recently published work. Specifically, the research objectives were the following:
-Decipher how interactions with splicing factors could impact Hox tissue-specific functions
-Enlarge the cooperative role of mRNA processing regulators and HOX proteins
As outcomes of the project, we have characterised the interaction between the Hox TF Ultrabithorax (Ubx) and splicing factors in the mesoderm of Drosophila embryos. We have generated a genetic toolkit for studying Ubx splicing function and the toolkit for assessing the Ubx/splicing factors function in vivo is in progress. We have determined the conservation of HOX/splicing factors interaction in humans and established a protocol to identify the interactome of these complexes. Capturing these complexes and characterising their function as outlook will contribute to a better understanding of the mechanisms governing cell and tissue diversity and their deregulation in diseases.
