TY - JOUR
T1 - Substrate specificities of SR proteins in constitutive splicing are determined by their RNA recognition motifs and composite pre-mRNA exonic elements
AU - Mayeda, Akila
AU - Screaton, Gavin R.
AU - Chandler, Sharon D.
AU - Fu, Xiang Dong
AU - Krainer, Adrian R.
N1 - Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 1999/3
Y1 - 1999/3
N2 - We report striking differences in the substrate specificities of two human SR proteins, SF2/ASF and SC35, in constitutive splicing. β-Globin pre- mRNA (exons 1 and 2) is spliced indiscriminately with either SR protein. Human immunodeficiency virus tat pre-mRNA (exons 2 and 3) and immunoglobulin μ-chain (IgM) pre-mRNA (exons C3 and C4) are preferentially spliced with SF2/ASF and SC35, respectively. Using in vitro splicing with mutated or chimeric derivatives of the tat and IgM pre-mRNAs, we defined specific combinations of segments in the downstream exons, which mediate either positive or negative effects to confer SR protein specificity. A series of recombinant chimetic proteins consisting of domains of SF2/ASF and SC35 in various combinations was used to localize trans-acting domains responsible for substrate specificity. The RS domains of SF2/ASF and SC35 can be exchanged without effect on substrate specificity. The RNA recognition motifs (RRMs) of SF2/ASF are active only in the context of a two-RRM structure, and RRM2 has a dominant role in substrate specificity. In contrast, the single RRM of SC35 can function alone, but its substrate specificity can be influenced by the presence of an additional RRM. The RRMs behave as modules that, when present in different combinations, can have positive, neutral, or negative effects on splicing, depending upon the specific substrate. We conclude that SR protein-specific recognition of specific positive and negative pre-mRNA exonic elements via one or more RRMs is a crucial determinant of the substrate specificity of SR proteins in constitutive splicing.
AB - We report striking differences in the substrate specificities of two human SR proteins, SF2/ASF and SC35, in constitutive splicing. β-Globin pre- mRNA (exons 1 and 2) is spliced indiscriminately with either SR protein. Human immunodeficiency virus tat pre-mRNA (exons 2 and 3) and immunoglobulin μ-chain (IgM) pre-mRNA (exons C3 and C4) are preferentially spliced with SF2/ASF and SC35, respectively. Using in vitro splicing with mutated or chimeric derivatives of the tat and IgM pre-mRNAs, we defined specific combinations of segments in the downstream exons, which mediate either positive or negative effects to confer SR protein specificity. A series of recombinant chimetic proteins consisting of domains of SF2/ASF and SC35 in various combinations was used to localize trans-acting domains responsible for substrate specificity. The RS domains of SF2/ASF and SC35 can be exchanged without effect on substrate specificity. The RNA recognition motifs (RRMs) of SF2/ASF are active only in the context of a two-RRM structure, and RRM2 has a dominant role in substrate specificity. In contrast, the single RRM of SC35 can function alone, but its substrate specificity can be influenced by the presence of an additional RRM. The RRMs behave as modules that, when present in different combinations, can have positive, neutral, or negative effects on splicing, depending upon the specific substrate. We conclude that SR protein-specific recognition of specific positive and negative pre-mRNA exonic elements via one or more RRMs is a crucial determinant of the substrate specificity of SR proteins in constitutive splicing.
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U2 - 10.1128/MCB.19.3.1853
DO - 10.1128/MCB.19.3.1853
M3 - Article
C2 - 10022872
AN - SCOPUS:0033013977
VL - 19
SP - 1853
EP - 1863
JO - Molecular and Cellular Biology
JF - Molecular and Cellular Biology
SN - 0270-7306
IS - 3
ER -