FusionSpleißen

FusionSpleißen is a splicing phenomenon in which exons from distinct RNA transcripts are joined by the spliceosome to form fusion transcripts. These chimeric RNAs combine genetic material from two or more genes and can be coding or noncoding. FusionSpleißen is distinct from conventional cis-splicing, which joins exons within a single transcript, though its occurrence can be linked to transcriptional read-through or genome rearrangements.

Mechanisms and categories: FusionSpleißen can arise through trans-splicing, in which two separate pre-mRNAs are spliced together, or through read-through transcripts that extend into neighboring genes and are subsequently processed by alternative splice sites. In some cases, the phenomenon may reflect artifacts of sequencing or alignment, underscoring the need for careful validation.

Detection and validation: Identification relies on RNA sequencing methods that reveal junction reads spanning two genes. Long-read sequencing (for example, PacBio or Nanopore) can confirm full-length fusion transcripts. Validation commonly involves RT-PCR across the fusion junction followed by Sanger sequencing.

Biological and clinical relevance: The biological role of FusionSpleißen is an area of active research. Some fusion transcripts are translated into hybrid proteins with altered functions, while others modulate gene regulation or RNA stability. In cancer and other diseases, gene fusions are well-established disease drivers, and FusionSpleißen–derived transcripts may serve as biomarkers or therapeutic targets, though many reported events require validation to distinguish biology from technical artifacts.