Bifunctional enzyme that acts both as an endopeptidase and 2-oxoglutarate-dependent monooxygenase (PubMed:28847961) (By similarity). Endopeptidase that cleaves histones N-terminal tails at the carboxyl side of methylated arginine or lysine residues, to generate 'tailless nucleosomes', which may trigger transcription elongation (PubMed:28847961). Preferentially recognizes and cleaves monomethylated and dimethylated arginine residues of histones H2, H3 and H4. After initial cleavage, continues to digest histones tails via its aminopeptidase activity (PubMed:28847961). Additionally, may play a role in protein biosynthesis by modifying the translation machinery. Acts as Fe(2+) and 2-oxoglutarate-dependent monooxygenase, catalyzing (S)-stereospecific hydroxylation at C-3 of 'Lys-22' of DRG1 and 'Lys-21' of DRG2 translation factors (TRAFAC), promoting their interaction with ribonucleic acids (RNA) (By similarity). 2-oxoglutarate + L-lysyl-[protein] + O2 = (3S)-3-hydroxy-L-lysyl-[protein] + CO2 + succinate Homodimer; disulfide-linked. Interacts with DRG1 and DRG2. This sequence was first thought to be an alternatively spliced isoform of Pla2g4b. It is derived from Jmjd7 which is located upstream of Pla2g4b. Most tissues also express read-through transcripts from Jmjd7 into the downstream Pla2g4b gene, some of which may encode fusion proteins combining the N-terminus of this protein with PLA2G4B protein.