A novel 40S multi-snRNP complex isolated from rat liver nuclei.
Two structurally distinct RNP complexes (MI and MII), each with a sedimentation value of approx. 40S, were isolated from rat liver nuclear extracts by sucrose gradient centrifugation and subsequent native gel electrophoresis of the 40S hnRNP-containing fractions. MII RNP contained the bulk of hnRNA and hnRNP proteins (i.e. the 32-45KD core proteins and polypeptides of 60-80 and 110-130KD). MI RNP was characterized by the exclusive presence of U-snRNAs (U1, U2, U4, U5 and U6), their well known snRNP polypeptides and a number of Sm-associated proteins in the range of 50-210KD. Immunoselection experiments employing a monoclonal antibody with an established specificity for the U2-snRNP-specific B" polypeptide proved that the RNA and protein components characteristic of MI were part of a single multi-snRNP unit. The prominent 200/210KD protein doublet of MI was identified immunochemically as the rat homologue of the yeast PRP8 protein, a known U5-associated splicing component. Based on the major biochemical and immunochemical features of MI and MII RNP complexes, we conclude that MII represents the monomeric 40S hnRNP structure, whereas MI defines a novel multi-snRNP entity.
Guialis
A
A
Institute of Biological Research and Biotechnology, National Hellenic Research Foundation, Athens, Greece.
Moraitou
M
M
Patrinou-Georgoula
M
M
Dangli
A
A
D000818:Animals; D015152:Blotting, Northern; D004587:Electrophoresis, Agar Gel; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D008099:Liver / Q000737:chemistry*; D009693:Nucleic Acid Hybridization; D011233:Precipitin Tests; D012313:RNA / Q000032:analysis; D051381:Rats; D012261:Ribonucleoproteins / Q000302:isolation & purification*; D017411:Ribonucleoproteins, Small Nuclear
D012261:Ribonucleoproteins; D017411:Ribonucleoproteins, Small Nuclear; D012313:RNA