Preferentially binds to euchromatin and modulates cellular transcription by counteracting linker histone-mediated chromatin compaction. Associates with nucleosomes in euchromatin and is largely excluded from constitutive heterochromatin. Expressed in liver, spleen, lung, heart, kidney, muscle and brain (at protein level). Widely expressed with highest levels in submaxillary gland, thymus, kidney and liver and lowest levels in brain, lung, pancreas and eye. At 7.5 dpc, expression is detected in the ectoplacental cone but not in embryonic tissues. By 9.5 dpc and 12.5 dpc, strongly expressed in the giant trophoblast, spongiotrophoblast and decidual cells of the placenta (at protein level). At 9.5 dpc and 11.5 dpc, weakly expressed in the developing embryo. Specifically targeted by its C-terminus to nucleosomes in euchromatin. Belongs to the HMGN family.