Specific cleavage of the 70-kDa protein component of the U1 small nuclear ribonucleoprotein is a characteristic biochemical feature of apoptotic cell death.

RNA and protein components of the U1 particle

L A Casciola-Rosen; D K Miller; G J Anhalt; A Rosen


Scholarcy highlights

  • RNA and protein components of the U1 particle
  • The U1 small nuclear ribonucleoprotein particleesis- ies examining the fate of nucleaarutoantigendsuring sential for splicing of precursor mRNA, an activity thaatpoptosis, we observedthat U1-7OkDa is cleaved in depends upon both thReNA and protein components of apoptotic cells byan enzyme that has the inhibition characterthe U1 particle
  • Apoptosis occursasynchronouslyin cell populations,with a well defined morphologiscequence.In adherent cultures, thrpereogressive phases of apoptosis have been described . 1)Apoptoticcells becomerounded, and pull apart fromtheir neighbors.2)Thesecells subsequently lose their attachment to the substratum and floatoff into the medium, where they progress alongthe terminal stages of apoptosis
  • Electrophoresis was performed on 10% SDS-polyacrylamide gels containing0.087% bithe blebbed apoptotic cells into individual apoptotic fragments which disperse into the surrounding medium
  • After centrifugation to remove nuclei, ICE assays were performed on the supernatants; again, no cleavage of U1-70kDa was obtained.We conclude that mature ICE does not cleave U1-7OkDa in apoptotic cells, but the sensitivity of this activity to iodoacetamide and the chloromethylketone protease inhibitors resemblesthat of ICE
  • The recideennttification in apoptotic cells of specific proteolytic cleavages of 3 nuclear proteins, is of great interest .Careful study of the functional consequences of U1-70kDa cleavage may yield novel insights into the mechanisms of apoptosis, as well as new information on RNA splicing during this form of cell death

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