Miniexons

Miniexons are small, alternatively spliced exons that are found within genes, often interrupting the coding sequence of a gene. They are typically between 5 and 55 nucleotides in length. The presence of miniexons can lead to the production of multiple different mRNAs from a single gene, with varying combinations of exons included or excluded in the final transcript.

The splicing of miniexons is often regulated by complex splice site sequences and recognition sites for the splicing machinery. In some cases, miniexons may be subject to tissue-specific or developmentally regulated splicing, leading to differences in their inclusion or exclusion across different cell types or developmental stages.

Miniexons have been identified in a wide range of organisms, including animals and plants. They are thought to play a role in modulating gene function and expression, particularly in situations where the standard consensus splice sites may not be sufficient to ensure accurate and efficient splicing.

In the context of human disease, aberrant inclusion or exclusion of miniexons has been implicated in a range of neurological disorders, including myotonic dystrophy and Huntington's disease. In these cases, the inclusion of expanded miniexons within the coding region of a gene can lead to the production of aberrant mRNAs and subsequent toxic protein. The study of miniexons in these contexts has shed light on the complexities of gene regulation and the transcriptome, and highlights the importance of accurate splicing in controlling gene expression.