Characterization of a Protein Complex Containing Spliceosomal
نویسنده
چکیده
SF3b is a U2 snRNP-associated protein complex essential for spliceosome assembly. Although evidence that SF3b contains the spliceosomal proteins SAPs 49, 130, 145, and 155 has accumulated, a protein-mediated association between all of these proteins has yet to be directly demonstrated. Here we report the isolation of a cDNA encoding SAP 130, which completes the cloning of the putative SF3b complex proteins. Using antibodies to SAP 130 and other putative SF3b components, we showed that SAPs 130, 145, and 155 are present in a protein complex in nuclear extracts and that these proteins associate with one another in purified U2 snRNP. Moreover, SAPs 155 and 130 interact with each other (directly or indirectly) within this complex, and SAPs 49 and 145 are known to interact directly with each other. Thus, together with prior work, our studies indicate that SAPs 49, 130, 145, and 155 are indeed components of SF3b. The Saccharomyces cerevisiae homologs of SAPs 49 and 145 are encoded by essential genes. We show here that the S. cerevisiae homologs of SAPs 130 and 155 (scSAP 130/RSE1 and scSAP 155, respectively) are also essential. Recently, the SF3b proteins were found in purified U12 snRNP, which functionally substitutes for U2 snRNP in the minor spliceosome. This high level of conservation, together with the prior observation that the SF3b proteins interact with pre-mRNA very close to the branch site, suggest that the SF3b complex plays a critical role near or at the spliceosome catalytic core.
منابع مشابه
One-dimensional Uranium(VI) Coordination Polymer Complex Containing Dimethyl and Trimethyl Phosphate Ligands: Synthesis, Spectroscopic Characterization, Thermal Analyses, and Crystal Structure
A new one-dimensional uranium(VI) coordination polymer, [UO2(μ-DMP)2(TMP)]n (1) (DMP is dimethyl phosphate and TMP is trimethyl phosphate), was prepared from the reaction of UO2(NO3)2.6H2O and TMP in in THF (THF is tetrahydrofuran) as a solvent. Suitable crystals of this complex for crystal structure determination were obtained by slow evaporation of the produced yellow solution at room tempera...
متن کاملBinuclear Nickel(II) Complex Containing 6-Methyl-2,2'-bipyridine and Chloride Ligands: Synthesis, Characterization, Thermal Analyses, and Crystal Structure Determination
A new binuclear complex of [{NiCl(6-mbipy)}2(μ-Cl)2] (1) was prepared from the reaction of NiCl2.6H2O and 6-methyl-2,2'-bipyridine (6-mbipy) in a mixture of methanol and acetonitrile. Suitable crystals of 1 for X-ray diffraction measurement were obtained by slow evaporation of the resulted green solution at room ...
متن کاملSynthesis, Characterization, and Crystal Structure Determination of Iron(III) Hetero-ligand Complex Containing Chloride, Dimethyl sulfoxide, pyridine-2, 6-dicarboxylate and Water, [Fe(Pydc)(DMSO)(H2O)Cl]
A new metal-organic compound, [Fe(Pydc)(DMSO)(H2O)Cl], (where Pydc is pyridine-2, 6-dicarboxylate and DMSO is dimethyl sulfoxide), has been synthesized and characterized by singlecrystal X-ray diffraction, TGA/DTA, IR and Raman spectroscopy. Green-yellow crystals,crystallized in the monoclinic system, space group P21/n, a = 7.2461(4) Å, b = 10.3018(4) Å, c =17.7667(10) Å, α = 90°, β = 90.014°(5...
متن کاملProtein composition and electron microscopy structure of affinity-purified human spliceosomal B complexes isolated under physiological conditions.
The spliceosomal B complex is the substrate that undergoes catalytic activation leading to catalysis of pre-mRNA splicing. Previous characterization of this complex was performed in the presence of heparin, which dissociates less stably associated components. To obtain a more comprehensive inventory of the B complex proteome, we isolated this complex under low-stringency conditions using two in...
متن کامل