Tissue-related and species-specific differences in the 2-5A oligomer size requirement for activation of 2-5A-dependent RNase.
2',5'-Oligoadenylate (2-5A)-dependent RNase (L or F) is the final enzyme in the 2-5A pathway and a key component in the molecular mechanism of interferon (IFN) action. Here we demonstrate differences in the 2-5A oligomer size requirement between rabbit 2-5A-dependent RNase from reticulocytes and from cultured kidney cells. The rabbit reticulocyte enzyme was activated by tetramer 2-5A, whereas the ribonuclease from rabbit kidney cells required only trimer 2-5A. Interestingly, in contrast to the 2-5A-dependent RNase from rabbit reticulocytes, that from murine reticulocytes could be activated by trimer 2-5A. Partial proteolysis of affinity-labeled, 80-kD 2-5A-dependent RNase from rabbit reticulocytes and rabbit kidney cells resulted in the same pattern of labeled peptides. However, the affinity labeling reaction with a 32P-labeled 2-5A analog did produce some different labeled polypeptides in rabbit kidney cell extract and rabbit reticulocyte lysate. These results could indicate specialized functions for the 2-5A system in different organ systems.
Krause
D
D
Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814.
Silverman
R H
RH
D000227:Adenine Nucleotides / Q000378:metabolism*; D000818:Animals; D001704:Biopolymers; D004789:Enzyme Activation / Q000502:physiology; D007668:Kidney / Q000201:enzymology*; D007739:L Cells; D051379:Mice; D008970:Molecular Weight; D009843:Oligoribonucleotides / Q000378:metabolism*; D009928:Organ Specificity; D011817:Rabbits; D012156:Reticulocytes / Q000201:enzymology*; D012260:Ribonucleases / Q000378:metabolism*; D013045:Species Specificity
D000227:Adenine Nucleotides; D001704:Biopolymers; D009843:Oligoribonucleotides; C023505:2',5'-oligoadenylate; D012260:Ribonucleases