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Updated: Feb 23, 2026

A Reporter Assay to Analyze Intronic microRNA Maturation in Mammalian Cells
Published on: June 16, 2022
miR18a and miR19a Recruit Specific Proteins for Splicing in Thyroid Cancer Cells
Marcelo M Paiva1, Edna T Kimura1, Patricia P Coltri2
1Department of Cell and Developmental Biology, Institute for Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil.
Background:
Thyroid cancer is one of the most frequent types of endocrine cancers. In most cases, thyroid cancers are caused by deregulated miRNA expression, especially involving the miR17-92 cluster. miR17-92 transcription is altered in several different tumor types including lymphoma, leukemia, and of the breast and thyroid. As an intronic cluster, miR17-92 must be processed during splicing and therefore interaction between microprocessor and spliceosome machineries is of major importance in understanding its expression.
Materials And Methods:
We investigated the protein composition of spliceosomes assembled on pre-RNAs containing intronic miR18a and miR19a, components of the miR17-92 cluster, using mass spectrometry.
Results:
Interestingly, we observed that proteins associated with intronic miR18a and miR19a are cell-specific, and are similar for both miRNAs analyzed. The only exception is the group of heterogeneous nuclear proteins that are commonly recruited by different cells.
Conclusion:
miRNA processing depends on cell-specific proteins and heterogeneous nuclear proteins have a general role in miRNA processing from introns.
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