Isolation of U1-snRNP(s) from Mouse Teratocarcinoma Cells Using Immunochemical and Biochemical Procedures: High Proportion of U1a-snRNP to U1b-snRNP

Abstract

An attempt was made to immunochemically and biochemically purify and characterize the U1-snRNP(s) of mouse embryonal carcinoma cells.
The results obtained by RNA analysis of U1-snRNP(s) purified immunochemically from embryoid bodies, F9 cells and PYS-2 cells indicated that the U1-snRNP(s) in these cells consisted of U1a-snRNP and U1b-snRNP. The proportion of U1a-snRNP to U1b-snRNP was also found to be high in the embryoid bodies and F9 cells. The U1a-snRNP predominance in U1-snRNP population was also detected in PYS-2 cells.
The immunochemically purified U1-snRNP population from liver nuclei of 129 syngeneic male mouse (129/sv), a host mouse for transplantable tetratocarcinoma OTT6050, and ICR male mouse, contained approximately equal levels of the two U1-snRNP species (U1a- and U1b-snRNP).
Partially purified U1-snRNP from embryoid bodies was also obtained by elu-
tion from a DEAE-Sepharose column at around 0.18M NH₄Cl or by fractionation by 5-20% linear sucrose gradient centrifugation. The electrophoretic RNA profiles of the partially purified U1-snRNP of embryoid bodies were similar to those obtained immunochemically.