This gene encodes a highly basic protein localized to the nucleus. The evolutionarily constrained open reading frame is found on a bicistronic transcript which has a downstream ORF encoding the small nuclear ribonucleoprotein polypeptide N. The upstream coding region utilizes the first three exons of the transcript, a region that has been identified as an imprinting center. Multiple transcription initiation sites have been identified and extensive alternative splicing occurs in the 5' untranslated region but the full-length nature of these transcripts has not been determined.