Estimation of the minimum mRNA splicing error rate in vertebrates

Area of Science:

• Molecular Biology
• Genetics
• Genomics

Background:

• Introns are removed from mRNA by splicing machinery in vertebrates.
• Splicing errors can lead to aberrant transcripts, genomic instability, and disease.
• Alternative splicing complicates accurate estimation of constitutive splicing error rates.

Purpose of the Study:

• To estimate the error frequency of constitutive mRNA splicing.
• To avoid bias introduced by alternative splicing.
• To characterize splice variant frequencies across different loci, tissues, and species.

Main Methods:

• Analysis of splice variant frequencies at HPRT, POLB, and TRPV1 loci.
• Examination across multiple tissues in six vertebrate species.
• Statistical analysis to determine error rates and identify patterns.

Main Results:

• Splice variant frequencies varied significantly among loci, tissues, and species.
• A consistent lowest observed frequency of approximately 0.1% aberrant transcripts per intron was identified.
• This rate is proposed as the "irreducible" error rate of splicing.

Conclusions:

• Constitutive mRNA splicing has a low, irreducible error rate of approximately 0.1% per intron.
• This error rate is attributed to combined replication errors by RNA polymerase II and spliceosome inaccuracies.
• Understanding splicing fidelity is crucial for genomic stability and disease prevention.