Abstract
Mobility of the phage T4 td intron depends on activity of an intron-encoded endonuclease (I-TevI), which cleaves a homologous intronless (delta In) target gene. The double-strand break initiates a recombination event that leads to intron transfer. We found previously that I-TevI cleaves td delta In target DNA 23-26 nucleotides upstream of the intron insertion site. DNase I-footprinting experiments and gel-shift assays indicate that I-TevI makes primary contacts around the intron insertion site. A synthetic DNA duplex spanning the insertion site but lacking the cleavage site was shown to bind I-TevI specifically, and when cloned, to direct cleavage into vector sequences. The behavior of the cloned duplex and that of deletion and insertion mutants support a primary role for sequences surrounding the insertion site in directing I-TevI binding, conferring cleavage ability, and determining cleavage polarity. On the other hand, sequences around the cleavage site were shown to influence cleavage efficiency and cut-site selection. The role of cleavage-site sequences in determining cleavage distance argues against a strict "ruler" mechanism for cleavage by I-TevI. The complex nature of the homing site recognized by this unusual type of endonuclease is considered in the context of intron spread.
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Selected References
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- Belfort M. Phage T4 introns: self-splicing and mobility. Annu Rev Genet. 1990;24:363–385. doi: 10.1146/annurev.ge.24.120190.002051. [DOI] [PubMed] [Google Scholar]
- Bell-Pedersen D., Galloway Salvo J. L., Belfort M. A transcription terminator in the thymidylate synthase (thyA) structural gene of Escherichia coli and construction of a viable thyA::Kmr deletion. J Bacteriol. 1991 Feb;173(3):1193–1200. doi: 10.1128/jb.173.3.1193-1200.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bell-Pedersen D., Quirk S. M., Aubrey M., Belfort M. A site-specific endonuclease and co-conversion of flanking exons associated with the mobile td intron of phage T4. Gene. 1989 Oct 15;82(1):119–126. doi: 10.1016/0378-1119(89)90036-x. [DOI] [PubMed] [Google Scholar]
- Bell-Pedersen D., Quirk S., Clyman J., Belfort M. Intron mobility in phage T4 is dependent upon a distinctive class of endonucleases and independent of DNA sequences encoding the intron core: mechanistic and evolutionary implications. Nucleic Acids Res. 1990 Jul 11;18(13):3763–3770. doi: 10.1093/nar/18.13.3763. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chang A. C., Cohen S. N. Construction and characterization of amplifiable multicopy DNA cloning vehicles derived from the P15A cryptic miniplasmid. J Bacteriol. 1978 Jun;134(3):1141–1156. doi: 10.1128/jb.134.3.1141-1156.1978. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chu F. K., Maley G., Pedersen-Lane J., Wang A. M., Maley F. Characterization of the restriction site of a prokaryotic intron-encoded endonuclease. Proc Natl Acad Sci U S A. 1990 May;87(9):3574–3578. doi: 10.1073/pnas.87.9.3574. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Colleaux L., D'Auriol L., Galibert F., Dujon B. Recognition and cleavage site of the intron-encoded omega transposase. Proc Natl Acad Sci U S A. 1988 Aug;85(16):6022–6026. doi: 10.1073/pnas.85.16.6022. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Delahodde A., Goguel V., Becam A. M., Creusot F., Perea J., Banroques J., Jacq C. Site-specific DNA endonuclease and RNA maturase activities of two homologous intron-encoded proteins from yeast mitochondria. Cell. 1989 Feb 10;56(3):431–441. doi: 10.1016/0092-8674(89)90246-8. [DOI] [PubMed] [Google Scholar]
- Dujon B., Belfort M., Butow R. A., Jacq C., Lemieux C., Perlman P. S., Vogt V. M. Mobile introns: definition of terms and recommended nomenclature. Gene. 1989 Oct 15;82(1):115–118. doi: 10.1016/0378-1119(89)90035-8. [DOI] [PubMed] [Google Scholar]
- Dujon B. Group I introns as mobile genetic elements: facts and mechanistic speculations--a review. Gene. 1989 Oct 15;82(1):91–114. doi: 10.1016/0378-1119(89)90034-6. [DOI] [PubMed] [Google Scholar]
- Muscarella D. E., Ellison E. L., Ruoff B. M., Vogt V. M. Characterization of I-Ppo, an intron-encoded endonuclease that mediates homing of a group I intron in the ribosomal DNA of Physarum polycephalum. Mol Cell Biol. 1990 Jul;10(7):3386–3396. doi: 10.1128/mcb.10.7.3386. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Perlman P. S., Butow R. A. Mobile introns and intron-encoded proteins. Science. 1989 Dec 1;246(4934):1106–1109. doi: 10.1126/science.2479980. [DOI] [PubMed] [Google Scholar]
- Quirk S. M., Bell-Pedersen D., Belfort M. Intron mobility in the T-even phages: high frequency inheritance of group I introns promoted by intron open reading frames. Cell. 1989 Feb 10;56(3):455–465. doi: 10.1016/0092-8674(89)90248-1. [DOI] [PubMed] [Google Scholar]
- Quirk S. M., Bell-Pedersen D., Tomaschewski J., Rüger W., Belfort M. The inconsistent distribution of introns in the T-even phages indicates recent genetic exchanges. Nucleic Acids Res. 1989 Jan 11;17(1):301–315. doi: 10.1093/nar/17.1.301. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Revzin A. Gel electrophoresis assays for DNA-protein interactions. Biotechniques. 1989 Apr;7(4):346–355. [PubMed] [Google Scholar]
- Ross W., Landy A., Kikuchi Y., Nash H. Interaction of int protein with specific sites on lambda att DNA. Cell. 1979 Oct;18(2):297–307. doi: 10.1016/0092-8674(79)90049-7. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Singh H., Sen R., Baltimore D., Sharp P. A. A nuclear factor that binds to a conserved sequence motif in transcriptional control elements of immunoglobulin genes. Nature. 1986 Jan 9;319(6049):154–158. doi: 10.1038/319154a0. [DOI] [PubMed] [Google Scholar]
- Studier F. W., Rosenberg A. H., Dunn J. J., Dubendorff J. W. Use of T7 RNA polymerase to direct expression of cloned genes. Methods Enzymol. 1990;185:60–89. doi: 10.1016/0076-6879(90)85008-c. [DOI] [PubMed] [Google Scholar]
- Wenzlau J. M., Saldanha R. J., Butow R. A., Perlman P. S. A latent intron-encoded maturase is also an endonuclease needed for intron mobility. Cell. 1989 Feb 10;56(3):421–430. doi: 10.1016/0092-8674(89)90245-6. [DOI] [PubMed] [Google Scholar]
- West D. K., Changchien L. M., Maley G. F., Maley F. Evidence that the intron open reading frame of the phage T4 td gene encodes a specific endonuclease. J Biol Chem. 1989 Jun 25;264(18):10343–10346. [PubMed] [Google Scholar]