RNA Processing in C. elegans - Caenorhabditis Elegans: Molecular Genetics and Development - page 208

As upstream genes in an operon are transcribed, CPSF and CstF stimulate 3 0 end
formation at the end of each gene-encoding section. RNA polymerase termination,
usually coupled with 3 0 end formation, is suspended. It is possible that this is
mediated by the CstF64 interaction with the SL2 snRNP, which is used specifically
to trans-splice downstream genes in operons. Downstream SL2 specificity appears
to be ensured by the Ur element in the ICR, which is capable of base pairing with the
SL2 snRNP after its arrival during upstream 3 0 end formation. The RNA duplex may
be sufficient to protect the downstream RNA from degradation until trans-splicing
places a new cap on its 5 0 end. It is also possible that recently discovered proteins
CIDS-1 or CIDS-2 may play some role in coordinating 3 0 end formation, trans-
splicing, and transcription termination in C. elegans operons.
Acknowledgments
The authors thank PegMacMorris and Erika Lasda for their careful reading of this manuscript and their
numerous helpful suggestions.
References
Aebi, M., Hornig, H., and Weissmann, C. (1987). 5 0 cleavage site in eukaryotic pre-mRNA splicing is
determined by the overall 5 0 splice region, not by the conserved 5 0 GU. Cell 50 , 237-246.
Allen, M. A., Hillier, L. W., Waterston, R. H., and Blumenthal, T. (2011). A global analysis of trans-
splicing. Genome Res. 21 , 255-264.
Arigo, J. T., Eyler, D. E., Carroll, K. L., and Corden, J. L. (2006). Termination of cryptic unstable
transcripts is directed by yeast RNA-binding proteins Nrd1 and Nab3. Mol. Cell 23 , 841-851.
Aroian, R. V., Levy, A. D., Koga, M., Ohshima, Y., Kramer, J. M., and Sternberg, P. W. (1993). Splicing in
Caenorhabditis elegans does not require an AG at the 3 0 splice acceptor site. Mol. Cell Biol. 13 ,
626-637.
Baugh, L. R., Demodena, J., and Sternberg, P. W. (2009). RNA Pol II accumulates at promoters of growth
genes during developmental arrest. Science 324 , 92-94.
Bektesh, S., Van Doren, K., and Hirsh, D. (1988). Presence of the Caenorhabditis elegans spliced leader
on different mRNAs and in different genera of nematodes. Genes Dev. 2 , 1277-1283.
Bektesh, S. L., and Hirsh, D. I. (1988). C. elegans mRNAs acquire a spliced leader through a trans-splicing
mechanism. Nucleic Acids Res. 16 , 5692.
Berglund, J. A., Abovich, N., and Rosbash, M. (1998). A cooperative interaction between U2AF65 and
mBBP/SF1 facilitates branchpoint region recognition. Genes Dev. 12 , 858-867.
Blumenthal, T. (1998). Gene clusters and polycistronic transcription in eukaryotes. Bioessays 20 ,
480-487.
Blumenthal, T. (1995). Trans-splicing and polycistronic transcription in Caenorhabditis elegans. Trends
Genet. 11 , 132-136.
Blumenthal, T., and Thomas, J. (1988). Cis and trans mRNA splicing in C. elegans. Trends Genet. 4 ,
305-308.
Blumenthal, T. (2004). Operons in eukaryotes. Briefings Funct. Genomics Proteomics 3 , 199-211.
Blumenthal, T. (2005). Trans-Splicing and Operons (2005). In (WormBook, ed.). The C. elegans Research
Community (Wormbook, doi/10.1895/wormbook.1.5.1). Available at: http://www.wormbook.org .
Blumenthal, T., Evans, D., Link, C. D., Guffanti, A., Lawson, D., Thierry-Mieg, J., Thierry-Mieg, D., Chiu,
W. L., Duke, K., and Kiraly, M., et al. (2002). A global analysis of Caenorhabditis elegans operons.
Nature 417 , 851-854.