Identification of an erythroid-enriched endoribonuclease activity involved in specific mRNA cleavage.
Stability of the human alpha-globin mRNA is conferred by a ribonucleoprotein complex termed the alpha-complex, which acts by impeding deadenylation. Using our recently devised in vitro decay assay, we demonstrate that the alpha-complex also functions by protecting the 3'-untranslated region (3'-UTR) from an erythroid-enriched, sequence-specific endoribonuclease activity. The cleavage site was mapped to a region protected by the alpha-complex and is regulated by the presence of the alpha-complex. Similar endoribonuclease cleavage products were also detected in erythroid cells expressing an exogenous alpha-globin gene. Nucleotide substitution of the target sequence renders the RNA refractory to the endoribonuclease activity. Insertion of the target sequence onto a heterologous RNA confers sequence-specific cleavage on the chimeric RNA, demonstrating the sequence specificity of this activity. We conclude that the alpha-complex stabilizes the alpha-globin mRNA in erythroid cells by a multifaceted approach, one aspect of which is to protect the 3'-UTR from specific endoribonuclease cleavage.
Wang
Z
Z
Rutgers University, Department of Cell Biology and Neuroscience, 604 Allison Road, Piscataway, NJ 08854-8082, USA.
Kiledjian
M
M
D020413:3' Untranslated Regions / Q000235:genetics; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D002678:Chimera; D018388:Codon, Terminator; D004722:Endoribonucleases / Q000378:metabolism*; D005914:Globins / Q000235:genetics*; D006801:Humans; D004915:Leukemia, Erythroblastic, Acute; D051379:Mice; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis; D012261:Ribonucleoproteins / Q000378:metabolism*; D013379:Substrate Specificity; D014162:Transfection; D014407:Tumor Cells, Cultured
D020413:3' Untranslated Regions; D018388:Codon, Terminator; D012333:RNA, Messenger; D011994:Recombinant Proteins; D012261:Ribonucleoproteins; D000255:Adenosine Triphosphate; D005914:Globins; D004722:Endoribonucleases