scholarly journals The U1 RNA-binding site of the U1 small nuclear ribonucleoprotein (snRNP)-associated A protein suggests a similarity with U2 snRNPs.

1989 ◽  
Vol 9 (7) ◽  
pp. 2975-2982 ◽  
Author(s):  
C Lutz-Freyermuth ◽  
J D Keene ◽  
C Lutz-Reyermuth

The site of interaction between human U1 RNA and one of its uniquely associated proteins, A, was examined with in vitro binding assays. The A protein bound directly to stem-loop II of U1 RNA in a region which exhibits sequence similarity to U2 RNA. The similarity with U2 RNA was in a region that has been shown to interact with a U2 RNA-associated protein. The A protein-binding site on U1 RNA overlapped a previously described epitope for an RNA-specific human autoantibody (S. L. Deutscher and J. D. Keene, Proc. Natl. Acad. Sci. USA 85:3299-3303, 1988), supporting the hypothesis that the anti-RNA antibody originated as an anti-idiotypic response to A protein-specific autoantibodies.

1989 ◽  
Vol 9 (7) ◽  
pp. 2975-2982
Author(s):  
C Lutz-Freyermuth ◽  
J D Keene ◽  
C Lutz-Reyermuth

The site of interaction between human U1 RNA and one of its uniquely associated proteins, A, was examined with in vitro binding assays. The A protein bound directly to stem-loop II of U1 RNA in a region which exhibits sequence similarity to U2 RNA. The similarity with U2 RNA was in a region that has been shown to interact with a U2 RNA-associated protein. The A protein-binding site on U1 RNA overlapped a previously described epitope for an RNA-specific human autoantibody (S. L. Deutscher and J. D. Keene, Proc. Natl. Acad. Sci. USA 85:3299-3303, 1988), supporting the hypothesis that the anti-RNA antibody originated as an anti-idiotypic response to A protein-specific autoantibodies.


1989 ◽  
Vol 9 (11) ◽  
pp. 4872-4881 ◽  
Author(s):  
C C Query ◽  
R C Bentley ◽  
J D Keene

We have defined the nucleotide sequence of a protein-binding domain within U1 RNA that specifically recognizes and binds both to a U1 small nuclear ribonucleoprotein component (the 70K protein) and to the previously defined RNA-binding domain of the 70K protein. We have investigated direct interactions between purified U1 RNA and 70K protein by reconstitution in vitro. Thirty-one nucleotides of U1 RNA, corresponding to stem-loop I, were required for this interaction. Nucleotides at the 5' end of U1 RNA that are involved in base pairing with the 5' splice site of pre-mRNA were not required for binding. In contrast to other reports, these findings demonstrate that a specific domain of U1 RNA can bind directly to the 70K protein independently of any other snRNP-associated proteins.


1989 ◽  
Vol 9 (11) ◽  
pp. 4872-4881
Author(s):  
C C Query ◽  
R C Bentley ◽  
J D Keene

We have defined the nucleotide sequence of a protein-binding domain within U1 RNA that specifically recognizes and binds both to a U1 small nuclear ribonucleoprotein component (the 70K protein) and to the previously defined RNA-binding domain of the 70K protein. We have investigated direct interactions between purified U1 RNA and 70K protein by reconstitution in vitro. Thirty-one nucleotides of U1 RNA, corresponding to stem-loop I, were required for this interaction. Nucleotides at the 5' end of U1 RNA that are involved in base pairing with the 5' splice site of pre-mRNA were not required for binding. In contrast to other reports, these findings demonstrate that a specific domain of U1 RNA can bind directly to the 70K protein independently of any other snRNP-associated proteins.


1994 ◽  
Vol 14 (9) ◽  
pp. 6337-6349 ◽  
Author(s):  
S E Wells ◽  
M Ares

Binding of U2 small nuclear ribonucleoprotein (snRNP) to the pre-mRNA is an early and important step in spliceosome assembly. We searched for evidence of cooperative function between yeast U2 small nuclear RNA (snRNA) and several genetically identified splicing (Prp) proteins required for the first chemical step of splicing, using the phenotype of synthetic lethality. We constructed yeast strains with pairwise combinations of 28 different U2 alleles with 10 prp mutations and found lethal double-mutant combinations with prp5, -9, -11, and -21 but not with prp3, -4, -8, or -19. Many U2 mutations in highly conserved or invariant RNA structures show no phenotype in a wild-type PRP background but render mutant prp strains inviable, suggesting that the conserved but dispensable U2 elements are essential for efficient cooperative function with specific Prp proteins. Mutant U2 snRNA fails to accumulate in synthetic lethal strains, demonstrating that interaction between U2 RNA and these four Prp proteins contributes to U2 snRNP assembly or stability. Three of the proteins (Prp9p, Prp11p, and Prp21p) are associated with each other and pre-mRNA in U2-dependent splicing complexes in vitro and bind specifically to synthetic U2 snRNA added to crude splicing extracts depleted of endogenous U2 snRNPs. Taken together, the results suggest that Prp9p, -11p, and -21p are U2 snRNP proteins that interact with a structured region including U2 stem loop IIa and mediate the association of the U2 snRNP with pre-mRNA.


1987 ◽  
Vol 7 (7) ◽  
pp. 2588-2591 ◽  
Author(s):  
E K Chan ◽  
E M Tan

SS-B/La is a nuclear protein of 48 kilodaltons with two structural domains of Mr 28,000 and Mr 23,000 generated by proteolytic cleavage. UV irradiation was used to cross-link preexisting intracellular La-RNA complexes. Subsequent protease digestion and diagonal gel electrophoresis showed that the RNA-binding site resided in the nonphosphorylated, methionine-rich 28-kilodalton domain.


1987 ◽  
Vol 7 (7) ◽  
pp. 2588-2591
Author(s):  
E K Chan ◽  
E M Tan

SS-B/La is a nuclear protein of 48 kilodaltons with two structural domains of Mr 28,000 and Mr 23,000 generated by proteolytic cleavage. UV irradiation was used to cross-link preexisting intracellular La-RNA complexes. Subsequent protease digestion and diagonal gel electrophoresis showed that the RNA-binding site resided in the nonphosphorylated, methionine-rich 28-kilodalton domain.


2018 ◽  
Vol 29 (15) ◽  
pp. 1878-1890 ◽  
Author(s):  
Hana M. Odeh ◽  
Etienne Coyaud ◽  
Brian Raught ◽  
Michael J. Matunis

Sumoylation regulates a wide range of essential cellular functions, many of which are associated with activities in the nucleus. Although there is also emerging evidence for the involvement of the small ubiquitin-related modifier (SUMO) at intracellular membranes, the mechanisms by which sumoylation is regulated at membranes is largely unexplored. In this study, we report that the SUMO-specific isopeptidase, SENP2, uniquely associates with intracellular membranes. Using in vivo analyses and in vitro binding assays, we show that SENP2 is targeted to intracellular membranes via a predicted N-terminal amphipathic α-helix that promotes direct membrane binding. Furthermore, we demonstrate that SENP2 binding to intracellular membranes is regulated by interactions with the nuclear import receptor karyopherin-α. Consistent with membrane association, biotin identification (BioID) revealed interactions between SENP2 and endoplasmic reticulum, Golgi, and inner nuclear membrane-associated proteins. Collectively, our findings indicate that SENP2 binds to intracellular membranes where it interacts with membrane-associated proteins and has the potential to regulate their sumoylation and membrane-associated functions.


1996 ◽  
Vol 16 (6) ◽  
pp. 2787-2795 ◽  
Author(s):  
J Tang ◽  
N Abovich ◽  
M Rosbash

The inessential yeast gene MUD2 encodes a protein factor that contributes to U1 small nuclear ribonucleoprotein particle (snRNP)-pre-mRNA complex (commitment complex) formation. To identify other genes that contribute to this early splicing step, we performed a synthetic lethal screen with a MUD2 deletion strain. The first characterized gene from this screen, MSL1 (MUD synthetic lethal 1), encodes the yeast homolog of the well studied mammalian snRNP protein U2B". The yeast protein (YU2B") is a component of yeast U2 snRNP, and it is related to other members of the UIA-U2B" family, the human U2B" protein, the human U1A protein, and the yeast U1A protein. It binds in vitro to its RNA target, U2 snRNA stem-loop IV, without a protein cofactor, and the target resembles more closely the U1 snRNA binding site of the human U1A protein than it does the U2 snRNA binding site of human U2B". Surprisingly, the YU2B" protein lacks a C-terminal RNA binding domain, which is conserved in all other family members. Possible functional and evolutionary relationships among these proteins are discussed.


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