Effects of PTCs on nonsense-mediated mRNA decay are dependent on PTC location

Area of Science:

• Molecular Biology
• Cancer Research
• Genetics

Background:

• The récepteur d'origine nantais (RON) gene encodes a receptor tyrosine kinase involved in cell signaling.
• Aberrant RON signaling and specific isoforms like RONΔ160 are implicated in cancer progression and metastasis.
• Nonsense-mediated mRNA decay (NMD) is a surveillance pathway that degrades mRNAs containing premature termination codons (PTCs).

Purpose of the Study:

• To investigate the impact of PTCs within alternative exons 5 and 6 of the RON gene on alternative splicing and NMD.
• To elucidate the role of PTC location in modulating NMD efficiency and isoform generation.

Main Methods:

• Utilized minigene constructs with PTCs inserted at various locations in RON exons 5 and 6.
• Analyzed mRNA expression of different RON isoforms using RT-PCR and sequencing.
• Assessed the influence of PTCs on NMD pathway activation.

Main Results:

• PTCs in alternative exons 5 and 6 of RON induced NMD for most spliced isoforms.
• Isoforms lacking exon 6 or both exons 5 and 6 were significantly increased upon PTC introduction.
• The effect of PTCs on NMD and isoform generation was dependent on the PTC's specific location within the exons.

Conclusions:

• A novel mechanism regulating NMD in the context of alternative splicing of the RON gene was identified.
• PTC location critically influences NMD activity and the production of specific RON isoforms.
• Findings suggest a complex interplay between NMD, alternative splicing, and oncogenic signaling pathways involving RON.