scholarly journals Overexpression of Essential Splicing Factor ASF/SF2 Blocks the Temporal Shift in Adenovirus Pre-mRNA Splicing and Reduces Virus Progeny Formation

2000 ◽  
Vol 74 (19) ◽  
pp. 9002-9009 ◽  
Author(s):  
Magnus Molin ◽  
Göran Akusjärvi
Keyword(s):  
Splice Site ◽  
Site Selection ◽  
Recombinant Adenovirus ◽  
Mrna Splicing ◽  
General Tendency ◽  
Viral Control ◽  
Splice Site Selection ◽  
Sr Protein ◽  
Virus Growth ◽  
Temporal Shift

ABSTRACT Expression of cytoplasmic mRNA from most adenovirus transcription units is subjected to a temporal regulation at the level of alternative pre-mRNA splicing. The general tendency is that splice site selection changes from proximal to distal late after infection. Interestingly, ASF/SF2, which is a prototypical member of the SR family of splicing factors, has the opposite effect on splice site selection, inducing an increase in proximal splice site usage. We have previously shown that SR proteins late during an adenovirus infection become partially inactivated as splicing regulatory proteins. A prediction from these results is that overexpression of an SR protein, such as ASF/SF2, during virus growth will interfere with virus replication by disturbing the balance of functional and nonfunctional ASF/SF2 in the infected cell. To test this hypothesis, we reconstructed a recombinant adenovirus expressing ASF/SF2 under the transcriptional control of a regulated promoter. The results show that, as predicted, induction of ASF/SF2 during lytic virus growth prevents the early to late shift in mRNA expression from both early (E1A and E1B) and late (L1) transcription units. Furthermore, ASF/SF2 overexpression blocks viral DNA replication and reduces selectively cytoplasmic accumulation of major late mRNA, resulting in a lower virus yield. Collectively, our results provide additional support for the hypothesis that viral control of SR protein function is important for the proper expression of viral proteins during lytic virus growth.

scholarly journals Promoter Choice Determines Splice Site Selection in Protocadherin α and γ Pre-mRNA Splicing

2002 ◽  
Vol 10 (1) ◽  
pp. 21-33 ◽  
Author(s):  
Bosiljka Tasic ◽  
Christoph E. Nabholz ◽  
Kristin K. Baldwin ◽  
Youngwook Kim ◽  
Erroll H. Rueckert ◽  
...  
Keyword(s):  
Splice Site ◽  
Site Selection ◽  
Mrna Splicing ◽  
Splice Site Selection

scholarly journals Mutagenesis of the Yeast Gene PRP8 Reveals Domains Governing the Specificity and Fidelity of 3′ Splice Site Selection

Genetics ◽  
1996 ◽  
Vol 143 (2) ◽  
pp. 723-739 ◽  
Author(s):  
James G Umen ◽  
Christine Guthrie
Keyword(s):  
Splice Site ◽  
Site Selection ◽  
Point Mutations ◽  
Genetic Data ◽  
Mrna Splicing ◽  
Terminal Portion ◽  
Yeast Gene ◽  
Splice Site Selection ◽  
Snrnp Protein ◽  
New Alleles

Abstract PRP8 encodes a highly conserved U5 snRNP protein required for spliceosome assembly and later steps of pre-mRNA splicing. We recently identified a novel allele, prp8-101, that specifically impairs recognition of the undine tract that precedes most yeast 3′ slice sites. We carried out extensive mutagenesis of the gene and selected for new alleles that confer a phenotype similar to that of prp8-101. The strongest alleles cause changes in one of two amino acids in the C-terminal portion of the protein. We also identified a second class of PRP8 mutant that affects the fidelity of 3′ splice site utilization. These alleles suppress point mutations in the PyAG motif at the 3′ splice site and do not alter uridine tract recognition. The strongest of these alleles map to a region directly upstream of the pp8-101-like mutations. These new PRP8 alleles define two separable functions of Prp8p, required for specificity of 3′ splice site selection and fidelity of 3′ splice site utilization, respectively. Taken together with other recent biochemical and genetic data, our results suggest that Prp8p plays a functional role at the active site of the spliceosome during the second catalytic step of splicing.

SR protein kinases: the splice of life

1999 ◽  
Vol 77 (4) ◽  
pp. 293-298 ◽  
Author(s):  
David F Stojdl ◽  
John C Bell
Keyword(s):  
Alternative Splicing ◽  
Splice Site ◽  
Site Selection ◽  
Developmental Process ◽  
Messenger Rnas ◽  
Splice Site Selection ◽  
Sr Protein ◽  
Specific Alternative ◽  
Mature Mrnas

The eukaryotic genome codes for most of its proteins though discontinuous coding sequences called exons, which are separated by noncoding sequences known as introns. Following transcription of a gene, these exons must be spliced precisely, removing the intervening introns, to form meaningful mature messenger RNAs (mRNA) that are transported to the cytoplasm and translated by the ribosomal machinery. To add yet another level of complexity, a process known as alternative splicing exists, whereby a single pre-mRNA can give rise to two or more mature mRNAs depending on the combination of exons spliced together. Alternative splicing of pre-mRNAs is emerging as an important mechanism for gene regulation in many organisms. The classic example of splicing as a regulator of genetic information during a developmental process is sex determination in Drosophila. The now well-characterized cascade of sex-specific alternative splicing events demonstrates nicely how the control of splice site selection during pre-mRNA processing can have a profound effect on the development of an organism. The factors involved in pre-mRNA splicing and alternative splice site selection have been the subject of active study in recent years. Emerging from these studies is a picture of regulation based on protein-protein, protein-RNA, and RNA-RNA interactions. How the interaction of the various splicing constituents is controlled, however, is still poorly understood. One of the mechanisms of regulation that has received attention recently is that of posttranslational phosphorylation. In the following article, we cite the evidence for a role of phosphorylation in constitutive and alternative splicing and discuss some of the recent information on the biochemistry and biology of the enzymes involved.Key words: phosphorylation, splicing, spliceosome, Clk kinases, SR proteins.

scholarly journals Recognizing the 35th anniversary of the proposal that snRNPs are involved in splicing

2015 ◽  
Vol 26 (20) ◽  
pp. 3557-3560
Author(s):  
Stephen M. Mount ◽  
Sandra L. Wolin
Keyword(s):  
Graduate Students ◽  
Molecular Biology ◽  
Splice Site ◽  
Rna Processing ◽  
Site Selection ◽  
Small Rnas ◽  
Mrna Splicing ◽  
Splice Site Selection ◽  
Pivotal Point ◽  
History Of

Thirty-five years ago, as young graduate students, we had the pleasure and privilege of being in Joan Steitz’s laboratory at a pivotal point in the history of RNA molecular biology. Introns had recently been discovered in the laboratories of Philip Sharp and Richard Roberts, but the machinery for removing them from mRNA precursors was entirely unknown. This Retrospective describes our hypothesis that recently discovered snRNPs functioned in pre-mRNA splicing. The proposal was proven correct, as has Joan’s intuition that small RNAs provide specificity to RNA processing reactions through base pairing in diverse settings. However, research over the intervening years has revealed that both splice site selection and splicing itself are much more complex and dynamic than we imagined.

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