Structure of two forms of the interferon-induced (2'-5') oligo A synthetase of human cells based on cDNAs and gene sequences.
The (2'-5') oligo A synthetase E, one of the translational inhibitory enzymes whose synthesis is strongly induced by all interferons (IFNs), is shown to be encoded in human cells by a 13.5-kb gene. By a cell-specific differential splicing, between the seventh and an additional eighth exon of this gene, two active E mRNAs of 1.6 and 1.8 kb are produced, along with several longer transcripts. cDNA clones for the two mRNAs were obtained and their sequences indicate that the human (2'-5') oligo A synthetase gene codes for two forms of the enzyme of mol. wt. 41 000 and 46 000, which differ only by their C-terminal ends. The product of the 1.6-kb RNA (E16) has a very hydrophobic C terminus, which is replaced by a longer acidic C-terminal sequence in the 1.8-kb RNA product (E18). The transcriptional start site of the gene was identified and 200 bp of the 5' flanking region were sequenced. A strong homology was found between this region of the IFN-activated (2'-5') oligo A synthetase gene and the corresponding region of the human fibroblast IFN-beta 1 gene, whose transcription is also stimulated by IFN priming. The gene has two polyadenylation sites which share a common undecanucleotide, but are used in a cell-specific manner to give rise to the 1.6- and 1.8-kb mRNAs.
P
P
Benech
Y
Y
Mory
M
M
Revel
J
J
Chebath
D015088:2',5'-Oligoadenylate Synthetase / Q000096:biosynthesis / Q000235:genetics*; D000595:Amino Acid Sequence; D001483:Base Sequence; D002051:Burkitt Lymphoma; D002460:Cell Line; D003001:Cloning, Molecular; D004247:DNA / Q000302:isolation & purification*; D004262:DNA Restriction Enzymes; D004790:Enzyme Induction; D005796:Genes; D006801:Humans; D007372:Interferons / Q000494:pharmacology*; D008297:Male; D009693:Nucleic Acid Hybridization; D011061:Poly A / Q000235:genetics; D012313:RNA / Q000235:genetics; D012333:RNA, Messenger; D012867:Skin / Q000201:enzymology; D014158:Transcription, Genetic
D012333:RNA, Messenger; D011061:Poly A; D012313:RNA; D004247:DNA; D007372:Interferons; D015088:2',5'-Oligoadenylate Synthetase; D004262:DNA Restriction Enzymes