Minigene Collection

What are minigenes?

A minigene contains a genomic fragment including the alternative exon(s) and the surrounding introns as well as the flanking constitutively spliced cloned in a eukaryotic expression vector.

Thus, the transfected minigenes should contain all RNA-elements necessary to show the same alternative splicing pattern as the corresponding endogenous alternatively spliced gene when compared in a specific cellular environment.

The in vivo minigene approach

The exact mechanisms leading to alternative splice site selection are still poorly understood. However, recently cotransfection studies in eukaryotic cells were successfully used to decipher contributions of RNA elements (cis-factors), their interacting protein components (trans-factors) or the cell type on alternative pre-mRNA splicing. Splice factors often work in a concentration dependent manner, resulting in a gradual change of alternative splicing patterns of a minigene when the amount of a trans-acting protein is increased by cotransfections.

Here, we provide a summary of 46 minigenes currently investigated.

Figure legend: Summary of minigenes that have been used to analyze alternative splicing patterns in vivo. The structures of the various genes are schematically indicated, however, the drawings are not to scale. The various genes are sorted according to their splicing mechanism (A-H). Exonic splicing enhancers/silencers (ESE/ESS) or intronic splicing enhancers/silencers (ISE/ISS) are indicated by triangles marked with a "+" or with a "-", respectively. In some cases, special abbreviations were used for well characterized cis-elements:

DCS: downstream control sequence

ICR: intronic control region

MSE: muscle specific splicing enhancer

IRE: intron regulatory element

PTB: Polypyrimidine tract binding protein binding site.

The tip of the triangle points towards the resulting splicing pattern.

cis-elements containing identical sequence elements are marked by the same color. Identified tissue specific trans-acting factors are shown on top or bottom of the minigenes, depending on the stimulatory or inhibitory effect, respectively. When a direct correlation between binding of a splicing factor to a cis-element and a change of splicing patterns has been demonstrated, cis-elements and trans-acting factors are shown in the same color.