hnRNA: An assortment of RNA molecules assembled around newly transcribed RNA (pre-
messenger RNA, or pre-mRNA) in the cell nucleus. The hnRNA associates with proteins
to form heterogeneous nuclear ribonucleoprotein (hnRNP). After release from the
chromosome and processing of the pre-mRNA by the spliceosome (see intron), the
mature messenger RNA remains associated with various proteins, forming a messenger
ribonucleoprotein (mRNP), which is then exported from the nucleus
hnRNP: Heterogeneous nuclear ribonucleoproteins (hnRNPs) are complexes of RNA and
protein present in the cell nucleus during gene transcription and subsequent post-
transcriptional modification of the newly synthesized RNA (pre-mRNA). The presence
of the proteins bound to a pre-mRNA molecule serves as a signal that the pre-mRNA is
not yet fully processed and ready for export to the cytoplasm. After splicing has
occurred, the proteins remain bound to spliced introns and target them for
snRNA: Short RNAs, and forms complexes with proteins in snRNPs. snRNAs are involved in
RNA processing such as splicing and polyadenylation.
snRNP: Small nuclear ribonucleoprotein (RNA plus protein) particle. Component of the
spliceosome, the intron-removing apparatus in eukaryotic nuclei .
mRNA: In prokaryotes, mRNA is derived from a large primary transcript from a DNA sequence.
The mRNAs of prokaryotes are usually very short lived (from seconds to more than an