Physical and biochemical properties of mammalian DNase X proteins: non-AUG translation initiation of porcine and bovine mRNAs for DNase X.
DNase X is the first human DNase protein identified as being homologous with DNase I. In the present study we describe the isolation of several mammalian DNase X cDNAs and the molecular characterization of their coding proteins. A sequence comparison reveals some conserved characteristics: all the mammalian DNase X proteins have an N-terminal signal peptide, a potential N-linked glycosylation site and a C-terminal hydrophobic domain. Human DNase X, ectopically expressed in HeLa S3 cells, is located in the ER (endoplasmic reticulum) and is modified by an N-linked glycosylation at Asn-243. Gene expression analyses show that the high expression level in muscular tissues, a known feature of human DNASE X, is also observed in mouse DNase X. Interestingly, the translation of porcine and bovine DNase X proteins occurs in the absence of an in-frame AUG initiation codon. We show that their mRNAs utilize a conserved CUG triplet for translation initiation.
Shiokawa
Daisuke
D
Department of Biochemistry, Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
Shika
Yukari
Y
Saito
Kazuki
K
Yamazaki
Kosuke
K
Tanuma
Sei-ichi
S
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D018387:Codon, Initiator / Q000235:genetics*; D016384:Consensus Sequence; D003851:Deoxyribonucleases / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D010442:Peptide Chain Initiation, Translational; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013552:Swine / Q000235:genetics*
D018387:Codon, Initiator; D012333:RNA, Messenger; D003851:Deoxyribonucleases