Operons in C. elegans: polycistronic mRNA precursors are processed by trans-splicing of SL2 to downstream coding regions.
The mRNAs of six C. elegans genes are known to be trans-spliced to SL2. We report here that a similarly oriented gene is located 100-300 bp upstream of each. We present evidence that the genes in these clusters are cotranscribed and downstream mRNAs are formed by cleavage at the polyadenylation site and trans-splicing. From one three-gene cluster we isolated cDNA clones representing both polycistronic RNAs and mRNAs polyadenylated at the free 3' end created by trans-splicing, suggesting that polycistronic RNAs can be processed by trans-splicing. Several experiments indicate that SL2 trans-splicing is a consequence of a gene's downstream location in an operon. In particular, when an SL1-accepting gene was moved to a downstream location, its mRNA was trans-spliced largely to SL2. The possible regulatory significance of cotranscription of C. elegans genes is discussed.
Spieth
J
J
Department of Biology, Indiana University, Bloomington 47405.
Brooke
G
G
Kuersten
S
S
Lea
K
K
Blumenthal
T
T
D000818:Animals; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000235:genetics*; D003001:Cloning, Molecular; D005796:Genes; D006360:Heat-Shock Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D009838:Oligodeoxyribonucleotides; D009876:Operon; D010957:Plasmids; D011061:Poly A / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods; D012322:RNA Precursors / Q000235:genetics*; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics*; D015183:Restriction Mapping; D014158:Transcription, Genetic
D006360:Heat-Shock Proteins; D009838:Oligodeoxyribonucleotides; D012322:RNA Precursors; D012333:RNA, Messenger; D011061:Poly A