JMJD6 Regulates Splicing of Its Own Gene Resulting in Alternatively Spliced Isoforms with Different Nuclear Targets

Int J Mol Sci. 2020 Sep 10;21(18):6618. doi: 10.3390/ijms21186618.


Jumonji-domain-containing protein 6 (JMJD6) is a Fe(II) and 2-oxogluterate (2OG) dependent oxygenase involved in gene regulation through post-translationally modifying nuclear proteins. It is highly expressed in many cancer types and linked to tumor progression and metastasis. Four alternatively-spliced jmjd6 transcripts were annotated. Here, we focus on the two most abundantly expressed ones, which we call jmjd6-2 and jmjd6-Ex5. TCGA SpliceSeq data revealed a significant decrease of jmjd6-Ex5 transcripts in patients and postmortem tissue of several tumors. The two protein isoforms are distinguished by their C-terminal sequences, which include a serine-rich region (polyS-domain) in JMJD6-2 that is not present in JMJD6-Ex5. Immunoprecipitation followed by LC-MS/MS for JMJD6-Ex5 shows that different sets of proteins interact with JMJD6-2 and JMJD6-Ex5 with only a few overlaps. In particular, we found TFIIF-associating CTD phosphatase (FCP1), proteins of the survival of motor neurons (SMN) complex, heterogeneous nuclear ribonucleoproteins (hnRNPs) and upstream binding factor (UBF) to interact with JMJD6-Ex5. Like JMJD6-2, both UBF and FCP1 comprise a polyS-domain. The polyS domain of JMJD6-2 might block the interaction with polyS-domains of other proteins. In contrast, JMJD6-2 interacts with many SR-like proteins with arginine/serine-rich (RS)-domains, including several splicing factors. In an HIV-based splicing reporter assay, co-expression of JMJD6-2 inhibited exon inclusion, whereas JMJD6-Ex5 did not have any effect. Furthermore, the silencing of jmjd6 by siRNAs favored jmjd6-Ex5 transcripts, suggesting that JMJD6 controls splicing of its own pre-mRNA. The distinct molecular properties of JMJD6-2 and JMJD6-Ex5 open a lead into the functional implications of the variations of their relative abundance in tumors.

Keywords: hydroxylation; polyS domain; splicing.

Publication types

  • Comparative Study

MeSH terms

  • HEK293 Cells
  • HeLa Cells
  • Humans
  • Jumonji Domain-Containing Histone Demethylases / genetics
  • Jumonji Domain-Containing Histone Demethylases / metabolism*
  • Neoplasms / metabolism
  • Protein Domains
  • Protein Isoforms / chemistry
  • Protein Isoforms / metabolism
  • RNA Splicing*


  • Protein Isoforms
  • JMJD6 protein, human
  • Jumonji Domain-Containing Histone Demethylases