Purification and characterization of a polysome-associated endoribonuclease that degrades c-myc mRNA in vitro.
The regulation of mRNA half-lives is determined by multiple factors, including the activity of the messenger RNases (mRNases) responsible for destroying mRNA molecules. Previously, we used cell-free mRNA decay assays to identify a polysome-associated endonuclease that cleaves c-myc mRNA within the coding region. A similar activity has been solubilized and partially purified from a high salt extract of adult rat liver polysomes. Based on a correlation between protein and enzyme activity, the endonuclease is tentatively identified as a approximately 39-kDa protein. It cleaves the coding region stability determinant of c-myc mRNA with considerable specificity. Cleavages occur predominantly in an A-rich segment of the RNA. The endonuclease is resistant to RNase A inhibitors, sensitive to vanadyl ribonucleoside complex, and dependent on magnesium. In these and other respects, the soluble enzyme we have purified resembles the polysome-associated c-myc mRNase.
Lee
C H
CH
McArdle Laboratory for Cancer Research, University of Wisconsin, Madison, Wisconsin 53706, USA.
Leeds
P
P
Ross
J
J
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D017931:DNA Primers; D018076:DNA, Complementary; D004722:Endoribonucleases / Q000302:isolation & purification / Q000378:metabolism*; D006868:Hydrolysis; D008099:Liver / Q000201:enzymology; D008297:Male; D008969:Molecular Sequence Data; D011132:Polyribosomes / Q000378:metabolism*; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D017931:DNA Primers; D018076:DNA, Complementary; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D004722:Endoribonucleases