[Ribonucleoproteins containing heterogeneous nuclear and messenger cytoplasmic RNA. Characteristics, structure and...

Following the study of Spirin, many authors have shown that cytoplasmic messenger RNA and heterogeneous nuclear RNA are complexed with specific proteins to form ribonucleoprotein particles (RNP). These RNP are heterogeneous in size and present a high protein to RNA ratio. Different observations suggest a polymeric structure for nuclear ribonucleoproteins but their protein composition is more clearly complex than that of cytoplasmic ribonucleoproteins. If we accept the following processing: heterogeneous nuclear RNP leads to free cytoplasmic RNP leads to polysomic RNP, the question arises as to what extent proteins originally present in nuclear RNP are conserved. Proteins more or less tightly bound to RNA have different roles: packing and protection of RNA, regulation during gene expression processing.