QKI7

QKI7 is one of the isoforms produced by the human QKI gene, which encodes an RNA-binding protein in the STAR family. The QKI gene generates multiple isoforms through alternative splicing, with QKI-5, QKI-6, and QKI-7 being the major forms. QKI-7 differs from other isoforms in its C-terminal sequence and is predominantly localized in the cytoplasm, whereas QKI-5 is mainly nuclear and QKI-6 has intermediate localization.

Proteins in the QKI family contain a KH (K homology) RNA-binding domain and Qua domains that define their RNA-binding and regulatory properties. They recognize specific RNA motifs known as QKI response elements (QREs) and regulate various post-transcriptional processes, including splicing, mRNA stability, localization, and translation. Through these actions, QKI proteins influence fundamental cellular processes such as differentiation, development, and the formation of myelin.

In the nervous system, QKI proteins play key roles in oligodendrocyte development and myelination by controlling the expression and localization of transcripts for myelin-related proteins. QKI-7, as a cytoplasmic isoform, participates in the post-transcriptional regulation of target mRNAs in several tissues and has been studied in contexts such as endothelial biology and cancer, where it can affect transcript output and cell behavior.

Clinical and research interest in QKI includes associations between QKI expression and neurological disorders and cancer, as well as the gene’s location at chromosome 6q26. The quaking mouse model, which exhibits tremors and dysmyelination, provided early insights into QKI’s essential roles in myelin biology.