| 1998 |
Crystal structure at 2.4 Å of the ternary U2B"/U2A'/U2 snRNA hairpin-loop IV complex revealed that U2A' leucine-rich repeats contact the RRM domain of U2B" on the surface opposite its RNA-binding face, and the basic C-terminal region of U2A' interacts with the RNA stem; this protein-protein interaction is required for U2B" to bind U2 snRNA specifically. |
X-ray crystallography at 2.4 Å resolution |
Nature |
High |
9716128
|
| 1990 |
U2B'' binds specifically to U2 snRNA only in the presence of the accessory protein U2A'; exchange of two nucleotides between U1 and U2 snRNAs or of eight amino acids between U1A and U2B'' reverses binding specificity, identifying major RNA-binding determinants. |
In vitro RNA binding assays with recombinant proteins and mutant RNAs/proteins |
Nature |
High |
2140872
|
| 1990 |
U2B'' and U2A' form a stable protein-protein complex in the absence of RNA; the minimal U2B'' fragment (amino acids 1–88) required for specific U2 RNA binding is also the minimal region for U2A' interaction; U2B'' residues 37–46 permit U2 RNA binding when contacted by U2A', while residues 14–25 reduce non-specific U1 RNA binding. |
In vitro protein-protein and protein-RNA binding assays with deletion/hybrid mutants of U2B'' |
The EMBO journal |
High |
2145152
|
| 1991 |
U2A' forms a weak but detectable interaction with U2 RNA (at the stem of hairpin IV) and a stable complex with U2B''; the U2A'-U2B''-U2 RNA ternary complex is stabilized by this weak U2A'-RNA contact; the region of U2A' essential for U2B'' binding spans amino acids 1–164. |
RNA-protein binding assays with wild-type and mutant U2A' proteins; mutant U2 RNA binding experiments |
Nucleic acids research |
High |
1826350
|
| 1994 |
U2B'' nuclear import can occur via two mechanisms: (1) an internal NLS (amino acids 90–146) related to U1A's NLS, and (2) a 'piggy-back' mechanism whereby interaction with U2A' mediates nuclear transport through sequences in the N-terminal RNP motif of U2B''; U2A' nuclear transport occurs independently of both U2B'' binding and U2 snRNA. |
Nuclear import assays in Xenopus oocytes and mammalian cells with deletion mutants and microinjection |
Journal of cell science |
Medium |
7983149
|
| 1998 |
U2A' enables U2B'' to discriminate the loop sequence of U2 snRNA hairpin IV from U1 snRNA hairpin II but plays no role in stem sequence discrimination; a single leucine residue in U1A (Leu-44) accounts for much of the intrinsic RNA-binding specificity difference between U1A and U2B''; U2A' binds U2B'' with ~500-fold greater affinity than U1A. |
In vitro RNA-binding assays with purified recombinant proteins, site-directed mutagenesis |
RNA (New York, N.Y.) |
High |
9814759
|
| 1998 |
In yeast, the U2B'' counterpart Yib9p (Msl1p) requires the U2A' counterpart Lea1p for association with U2 snRNA in vivo, even though Yib9p can bind U2 snRNA stem-loop IV in vitro alone; deletion of LEA1 and/or YIB9 impairs pre-mRNA splicing and blocks spliceosome assembly prior to U2 snRNP addition. |
Yeast genetics (deletion strains), in vitro splicing/spliceosome assembly assays, recombinant protein rescue |
The EMBO journal |
High |
9799242
|
| 2014 |
U2A' binds U2B'' with nanomolar affinity but binds U1A with only micromolar affinity; RNA-dependent cooperativity (thermodynamic linkage) between protein-protein and protein-RNA interactions ensures partitioning of the U2A'/U2B'' complex exclusively to the U2 snRNP. |
Fluorescence binding assays and isothermal titration calorimetry (ITC) with purified recombinant proteins |
Biochemistry |
High |
24866816
|
| 2011 |
Human U2B'' binds not only U2 snRNA stem-loop IV but also U1 snRNA stem-loop II and Drosophila U2 snRNA SLIV in vitro with similar thermodynamics, indicating a relaxed RNA-binding specificity compared to U1A. |
In vitro RNA-protein binding assays and thermodynamic measurements |
Biophysical chemistry |
Medium |
21684671
|
| 2007 |
In C. elegans, RNP-3 (U2B'') is U2 snRNP-associated and binds U2 snRNA even in the absence of U2A'; knockout of both rnp-2 (U1A) and rnp-3 (U2B'') is required for lethality, demonstrating functional redundancy; U1A can associate with U2 RNA when U2B'' is deleted. |
Co-immunoprecipitation, genetic knockouts, RNA co-precipitation in C. elegans |
Proceedings of the National Academy of Sciences of the United States of America |
Medium |
17535930
|
| 2024 |
SNRPB2 knockdown in TNBC cells causes skipping of exon 6 in MDM4 pre-mRNA generating the MDM4-S transcript, reducing MDM4 protein levels, which decreases Rb1 protein expression and inactivates E2F1 signaling, suppressing cell proliferation and invasion. |
siRNA knockdown, transcriptome/alternative splicing analysis, Western blot, cell proliferation and invasion assays |
Cancer science |
Medium |
39329452
|
| 2025 |
SNRPB2 stabilizes E2F4 protein by preventing its proteasomal degradation; SNRPB2 knockdown in esophageal squamous cell carcinoma cells reduces E2F4 levels and suppresses proliferation, migration, and invasion, which is rescued by E2F4 overexpression. |
siRNA knockdown, cycloheximide chase assay, rescue overexpression, in vitro and in vivo functional assays |
Frontiers in immunology |
Medium |
40612943
|
| 2026 |
SNRPB2 knockdown in breast cancer cells induces G2/M cell cycle arrest and alters alternative splicing events including HMGA2 splicing; proposed mechanism is that SNRPB2 regulates cell cycle progression partly through HMGA2 splicing modulation. |
siRNA knockdown, RNA-seq, RT-qPCR, cell cycle analysis |
Molecular biology reports |
Low |
42068395
|