An immature or incompletely processed mRNA molecule in eukaryotes originated from primary transcript (hnRNA) in the nucleus and need to be processed before it becomes a fully functional mature mRNA for transport into the cytoplasm.
The precursor mRNA is the initial form of mRNA in eukaryotes. It is formed by transcribing the genetic information from DNA molecule. Before it is moved into the cytoplasm for translation at the ribosomal site, the precursor mRNA undergoes extensive processing within the nucleus.
See also: mature mRNA