MCB
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
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 Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Sun, H.
Right arrow Articles by Chasin, L. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Sun, H.
Right arrow Articles by Chasin, L. A.

 Previous Article  |  Next Article 

Molecular and Cellular Biology, September 2000, p. 6414-6425, Vol. 20, No. 17
0270-7306/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.

Multiple Splicing Defects in an Intronic False Exon

Hanzhen Sun and Lawrence A. Chasin*

Department of Biological Sciences, Columbia University, New York, New York 10027

Received 25 February 2000/Returned for modification 17 April 2000/Accepted 15 June 2000

Splice site consensus sequences alone are insufficient to dictate the recognition of real constitutive splice sites within the typically large transcripts of higher eukaryotes, and large numbers of pseudoexons flanked by pseudosplice sites with good matches to the consensus sequences can be easily designated. In an attempt to identify elements that prevent pseudoexon splicing, we have systematically altered known splicing signals, as well as immediately adjacent flanking sequences, of an arbitrarily chosen pseudoexon from intron 1 of the human hprt gene. The substitution of a 5' splice site that perfectly matches the 5' consensus combined with mutation to match the CAG/G sequence of the 3' consensus failed to get this model pseudoexon included as the central exon in a dhfr minigene context. Provision of a real 3' splice site and a consensus 5' splice site and removal of an upstream inhibitory sequence were necessary and sufficient to confer splicing on the pseudoexon. This activated context also supported the splicing of a second pseudoexon sequence containing no apparent enhancer. Thus, both the 5' splice site sequence and the polypyrimidine tract of the pseudoexon are defective despite their good agreement with the consensus. On the other hand, the pseudoexon body did not exert a negative influence on splicing. The introduction into the pseudoexon of a sequence selected for binding to ASF/SF2 or its replacement with beta -globin exon 2 only partially reversed the effect of the upstream negative element and the defective polypyrimidine tract. These results support the idea that exon-bridging enhancers are not a prerequisite for constitutive exon definition and suggest that intrinsically defective splice sites and negative elements play important roles in distinguishing the real splicing signal from the vast number of false splicing signals.

* Corresponding author. Mailing address: 912 Fairchild, Department of Biological Sciences, Columbia University, New York, NY 10027. Phone: (212) 854-4645. Fax: (212) 531-0425. E-mail: lac2{at}columbia.edu.

Molecular and Cellular Biology, September 2000, p. 6414-6425, Vol. 20, No. 17
0270-7306/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.


This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. J. Virol. Eukaryot. Cell
Microbiol. Mol. Biol. Rev. Clin. Vaccine Immunol. All ASM Journals

Copyright © 2000 by the American Society for Microbiology. All rights reserved.