Skip Navigation

This Article
Right arrow Print PDF (3489K)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrow Commercial Re-use Guidelines
for Open Access NAR Content
Google Scholar
Right arrow Articles by Ehrenman, K.
Right arrow Articles by Belfort, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ehrenman, K.
Right arrow Articles by Belfort, M.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Nucleic Acids Research, 1989, Vol. 17, No. 22 9147-9163
© 1989

MOLECULAR BIOLOGY

Sequence specificity of the P6 pairing for splicing of the group I td intron of phage T4

Karen Ehrenman1,2,+, Renee Schroeder1,§, P.Scott Chandry1,2, Dwight H. Hall3 and Marlene Belfort1,4,*

1Wadsworth Center for Laboratories and Research, New York State Department of Health Empire State Plaza, P0 Box 509, Albany, NY 12201-0509, USA 2Albany Medical College 147 New Scotland Avenue, Albany NY 12208, USA 3School of Applied Biology, Georgia Institute of Technology Atlanta, GA 30332, USA 4School of Public Health Sciences, State University of New York at Albany Empire State Plaza, Albany, NY 12237, USA

*To whom correspondence should be addressed

Received August 9, 1989. Revised October 10, 1989. Accepted October 10, 1989.

Seventeen non-directed td- (thymidylate synthase-deficient) splicing-defective mutations isolated in phage T4 were localized within the catalytic core of the ribozyme. All of the mutations occur in conserved structural elements that form part of the td intron core secondary structure. Remarkably, seven of the seventeen independently isolated mutations clustered in the dinucleotide 5' element (P6[5'] of the putative two-base-pair P6 stem. An analysis of this region was undertaken by site-directed mutagenesis of the plasmid-borne td gene, leading to the following findings: First, the short P6 pairing in the td secondary structure model was verified with appropriate P6[5'] and P6[3'] compensatory mutations. Second, all P6[5'] and P6[3'] mutants are defective in the first step of splicing, guanosine dependent 5' splice site cleavage, whereas their activity at the 3' splice site is variable. Third, residual in vitro splicing activity of the mutants altered on only one side of the P6 pairing is correlated with the ability to form an alternative two-base-pair P6 stem. Fourth, the degree to which the compensatory mutants have their splicing activity restored is highly condition-dependent. Restoration of phenotype of the compensatory P6[5']:[3'] constructs is weak under stringent in vitro conditions as well as in vivo. This sequence specificity is consistent with phylogenetic conservation of the P6 pairing elements in group I introns, and suggests either structural constraints on the P6 stem or a dual function of one or both pairing elements.

+Present addresses: Fred Hutchinson Cancer Research Center, 1124 Columbia St., Seattle, WA 98104, USA

§Present addresses: Institut für Mikrobiologie und Genetik der Universitat Wien, Vienna, Austria


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer:
Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.