Exon 2 of human cathepsin B derives from an Alu element.
Transcripts for the cysteine protease cathepsin B are alternatively spliced in the untranslated regions (UTRs). We show that a cathepsin B probe containing 5'-UTR sequences hybridized to an RNA of approximately 300 nt in addition to the typical 2.2 and 4.0 kbp mRNAs. Within this 5'-UTR, exon 2 was found to be homologous to Alu repetitive elements. Specifically, exon 2 was part of an Alu element interspersed with the cathepsin B gene. The approximately 300 nt band that hybridized to our cathepsin B probe likely corresponds to Alu transcripts, which are known to accumulate in human cells. Indeed, a similarly migrating band was detected with an authentic Alu probe. Thus, we suggest that primary transcripts for cathepsin B contain Alu sequences which are preserved as exon 2 in some fully spliced mRNAs.
Berquin
I M
IM
Department of Pharmacology, Wayne State University, Detroit, MI 48201, USA.
Ahram
M
M
Sloane
B F
BF
D017398:Alternative Splicing / Q000235:genetics; D001483:Base Sequence; D001940:Breast; D002401:Cathepsin B / Q000235:genetics*; D002460:Cell Line; D015342:DNA Probes; D004847:Epithelial Cells; D005091:Exons / Q000235:genetics*; D005796:Genes / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics*; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid
D015342:DNA Probes; D012333:RNA, Messenger; D002401:Cathepsin B