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The d-isoAsp-25 variant of histone H2B is highly enriched in active chromatin: potential role in the regulation of gene expression?

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Approximately 12 % of histone H2B in mammalian brain contains an unusual d-aspartate residue in its N-terminal tail. Most of this d-aspartate is linked to the C-flanking glycine via an isopeptide bond. To explore the possible significance of these modifications, we generated an antibody to the d-isoaspartyl form of H2B, and used it to assess its levels in H2B associated with “active” vs. “silent” chromatin. We found that the d-isoaspartyl form of H2B appears to be highly enriched in the former. This irreversible modification could serve a novel regulatory function in gene expression.

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Enhanced chemiluminescence




Knockout (PIMT−/−)


Protein l-isoaspartyl methyltransferase


Polyvinylidene difluoride


Tris-buffered saline


Wild type (PIMT+/+)


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We thank the laboratory of Prof. Mark J. Mamula at the Yale University School of Medicine for providing us with the founder mice from which our colony was generated. Some of this work was funded by NIH Grant NS17269 to DWA.

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Correspondence to Dana W. Aswad.

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Qin, Z., Zhu, J.X. & Aswad, D.W. The d-isoAsp-25 variant of histone H2B is highly enriched in active chromatin: potential role in the regulation of gene expression?. Amino Acids 48, 599–603 (2016).

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