DNAJC17 is localized in nuclear speckles and interacts with splicing machinery components

Area of Science:

• Molecular Biology
• Genetics
• Cell Biology

Background:

• DNAJC17 is a heat shock protein (HSP40) family member implicated in congenital hypothyroidism and human diseases like retinal dystrophy and myeloproliferative disorders.
• Despite its disease relevance and widespread expression, the precise function of DNAJC17 remains largely unknown.
• Previous studies indicate DNAJC17 knockout mouse embryos are not viable, highlighting its essential role in early development.

Purpose of the Study:

• To elucidate the molecular function of DNAJC17 using high-throughput transcriptomic and proteomic analyses.
• To investigate the role of DNAJC17 in cellular processes, particularly gene expression and splicing.

Main Methods:

• High-throughput transcriptomic and proteomic analyses were employed to study DNAJC17 function.
• Cellular depletion of DNAJC17 was performed to assess its impact on gene expression.
• Protein-protein interactions were identified and validated using co-immunoprecipitation and co-localization studies.
• Functional assays involving minigene reporters and RNA-seq data analysis were used to evaluate splicing efficiency.

Main Results:

• Transcriptomic analysis of DNAJC17-depleted cells revealed alterations in genes related to general functional categories, primarily gene expression.
• Proteomic analysis identified specific functional networks associated with DNAJC17, with a significant enrichment of splicing-related proteins.
• DNAJC17 was validated to interact with spliceosomal components and co-localize with SC35 in nuclear speckles.
• Increased DNAJC17 levels enhanced minigene reporter splicing efficiency, while its depletion impaired genome-wide splicing efficiency.

Conclusions:

• The study strongly implicates DNAJC17 in splicing-related processes.
• DNAJC17 plays a critical role in regulating splicing efficiency at a global level.
• These findings support the essential function of DNAJC17 in early embryonic development and provide insights into its involvement in human diseases.