RNA, Heterogeneous Nuclear

**Definition:** Nuclear nonribosomal RNA larger than about 1000 nucleotides, the mass of which is rapidly synthesized and degraded within the cell nucleus. Some heterogeneous nuclear RNA may be a precursor to mRNA. However, the great bulk of total hnRNA hybridizes with nuclear DNA rather than with mRNA.

**Tree numbers:** - D13.444.735.628.806

**Synonyms:** - hnRNA - Heterogeneous Nuclear RNA