[Isolation and characterization of a new class of cytoplasmic RNP-particles from rabbit reticulocytes containing 7SL RNA].

Ribonucleoprotein particles with sedimentation coefficient of 12-14S were isolated from ribosome-free extracts of rabbit reticulocytes. The particles contain one RNA molecule, whose relative electrophoretic mobility and the 3'-terminal nucleotide sequence correspond to those of the 7SL RNA from mammalian cells and one type of polypeptide chains with a molecular weight of 80,000-85,000 Da. The nucleic component of these particles is identical to that of SRP from dog pancreatic cells but differs from the latter by the protein component.