Abstract
About half of Caenorhabditis elegans genes have a 1-2 bp mismatch to the canonical AAUAAA hexamer that signals 3' end formation. One rare variant, AGUAAA, is found at the 3' end of the mai-1 gene, the first gene in an operon also containing gpd-2 and gpd-3. When we expressed this operon under heat shock control, 3' end formation dependent on the AGUAAA was very inefficient, but could be rescued by a single bp change to create a perfect AAUAAA. When AGUAAA was present, most 3' ends formed at a different site, 100 bp farther downstream, right at the gpd-2 trans-splice site. Surprisingly, 3' end formation at this site did not require any observable match to the AAUAAA consensus. It is possible that 3' end formation at this site occurs by a novel mechanism--trans-splicing-dependent cleavage--as deletion of the trans-splice site prevented 3' end formation here. Changing the AGUAAA to AAUAAA also influenced the trans-splicing process: with AGUAAA, most of the gpd-2 product was trans-spliced to SL1, rather than SL2, which is normally used at downstream operon trans-splice sites. However, with AAUAAA, SL2 trans-splicing of gpd-2 was increased. Our results imply that (1) the AAUAAA consensus controls 3' end formation frequency in C. elegans; (2) the AAUAAA is important in determining SL2 trans-splicing events more than 100 bp downstream; and (3) in some circumstances, 3' end formation may occur by a trans-splicing-dependent mechanism.
Full Text
The Full Text of this article is available as a PDF (377.3 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Brenner S. The genetics of Caenorhabditis elegans. Genetics. 1974 May;77(1):71–94. doi: 10.1093/genetics/77.1.71. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Conrad R., Thomas J., Spieth J., Blumenthal T. Insertion of part of an intron into the 5' untranslated region of a Caenorhabditis elegans gene converts it into a trans-spliced gene. Mol Cell Biol. 1991 Apr;11(4):1921–1926. doi: 10.1128/mcb.11.4.1921. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Coolidge C. J., Patton J. G. Run-around PCR: a novel way to create duplications using polymerase chain reaction. Biotechniques. 1995 May;18(5):762–764. [PubMed] [Google Scholar]
- Huang X. Y., Hirsh D. A second trans-spliced RNA leader sequence in the nematode Caenorhabditis elegans. Proc Natl Acad Sci U S A. 1989 Nov;86(22):8640–8644. doi: 10.1073/pnas.86.22.8640. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kuersten S., Lea K., MacMorris M., Spieth J., Blumenthal T. Relationship between 3' end formation and SL2-specific trans-splicing in polycistronic Caenorhabditis elegans pre-mRNA processing. RNA. 1997 Mar;3(3):269–278. [PMC free article] [PubMed] [Google Scholar]
- Lee Y. H., Huang X. Y., Hirsh D., Fox G. E., Hecht R. M. Conservation of gene organization and trans-splicing in the glyceraldehyde-3-phosphate dehydrogenase-encoding genes of Caenorhabditis briggsae. Gene. 1992 Nov 16;121(2):227–235. doi: 10.1016/0378-1119(92)90126-a. [DOI] [PubMed] [Google Scholar]
- Manley J. L., Yu H., Ryner L. RNA sequence containing hexanucleotide AAUAAA directs efficient mRNA polyadenylation in vitro. Mol Cell Biol. 1985 Feb;5(2):373–379. doi: 10.1128/mcb.5.2.373. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mello C. C., Kramer J. M., Stinchcomb D., Ambros V. Efficient gene transfer in C.elegans: extrachromosomal maintenance and integration of transforming sequences. EMBO J. 1991 Dec;10(12):3959–3970. doi: 10.1002/j.1460-2075.1991.tb04966.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Spieth J., Brooke G., Kuersten S., Lea K., Blumenthal T. Operons in C. elegans: polycistronic mRNA precursors are processed by trans-splicing of SL2 to downstream coding regions. Cell. 1993 May 7;73(3):521–532. doi: 10.1016/0092-8674(93)90139-h. [DOI] [PubMed] [Google Scholar]
- Williams C., Xu L., Blumenthal T. SL1 trans splicing and 3'-end formation in a novel class of Caenorhabditis elegans operon. Mol Cell Biol. 1999 Jan;19(1):376–383. doi: 10.1128/mcb.19.1.376. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Zhao J., Hyman L., Moore C. Formation of mRNA 3' ends in eukaryotes: mechanism, regulation, and interrelationships with other steps in mRNA synthesis. Microbiol Mol Biol Rev. 1999 Jun;63(2):405–445. doi: 10.1128/mmbr.63.2.405-445.1999. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Zorio D. A., Cheng N. N., Blumenthal T., Spieth J. Operons as a common form of chromosomal organization in C. elegans. Nature. 1994 Nov 17;372(6503):270–272. doi: 10.1038/372270a0. [DOI] [PubMed] [Google Scholar]
