MeSH 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.;
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.