scholarly journals The function of the NineTeen Complex (NTC) in regulating spliceosome conformations and fidelity during pre-mRNA splicing

2010 ◽  
Vol 38 (4) ◽  
pp. 1110-1115 ◽  
Author(s):  
Rebecca Hogg ◽  
Joanne C. McGrail ◽  
Raymond T. O'Keefe
Keyword(s):  
Recent Work ◽  
Present Article ◽  
Essential Role ◽  
Mrna Splicing ◽  
Associated Proteins ◽  
Intron Removal ◽  
Identification And Characterization ◽  
Small Nuclear Ribonucleoproteins ◽  
Essential Support

The NineTeen Complex (NTC) of proteins associates with the spliceosome during pre-mRNA splicing and is essential for both steps of intron removal. The NTC and other NTC-associated proteins are recruited to the spliceosome where they participate in regulating the formation and progression of essential spliceosome conformations required for the two steps of splicing. It is now clear that the NTC is an integral component of active spliceosomes from yeast to humans and provides essential support for the spliceosomal snRNPs (small nuclear ribonucleoproteins). In the present article, we discuss the identification and characterization of the yeast NTC and review recent work in yeast that supports the essential role for this complex in the regulation and fidelity of splicing.

scholarly journals Identification and Characterization of Two Novel Proteins Affecting Fission Yeast γ-tubulin Complex Function

2004 ◽  
Vol 15 (5) ◽  
pp. 2287-2301 ◽  
Author(s):  
Srinivas Venkatram ◽  
Joseph J. Tasto ◽  
Anna Feoktistova ◽  
Jennifer L. Jennings ◽  
Andrew J. Link ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Complex Function ◽  
Novel Proteins ◽  
Astral Microtubule ◽  
Different Types ◽  
Associated Proteins ◽  
Microtubule Formation ◽  
Identification And Characterization ◽  
Microtubule Function

The γ-tubulin complex, via its ability to organize microtubules, is critical for accurate chromosome segregation and cytokinesis in the fission yeast, Schizosaccharomyces pombe. To better understand its roles, we have purified the S. pombe γ-tubulin complex. Mass spectrometric analyses of the purified complex revealed known components and identified two novel proteins (i.e., Mbo1p and Gfh1p) with homology to γ-tubulin–associated proteins from other organisms. We show that both Mbo1p and Gfh1p localize to microtubule organizing centers. Although cells deleted for either mbo1+ or gfh1+ are viable, they exhibit a number of defects associated with altered microtubule function such as defects in cell polarity, nuclear positioning, spindle orientation, and cleavage site specification. In addition, mbo1Δ and gfh1Δ cells exhibit defects in astral microtubule formation and anchoring, suggesting that these proteins have specific roles in astral microtubule function. This study expands the known roles of γ-tubulin complex components in organizing different types of microtubule structures in S. pombe.

Roles of the U5 snRNP in spliceosome dynamics and catalysis

2004 ◽  
Vol 32 (6) ◽  
pp. 928-931 ◽  
Author(s):  
I.A. Turner ◽  
C.M. Norman ◽  
M.J. Churcher ◽  
A.J. Newman
Keyword(s):  
Mrna Splicing ◽  
Small Nuclear Rna ◽  
Protein Coding ◽  
Rna Molecules ◽  
Small Nuclear Ribonucleoprotein ◽  
Associated Proteins ◽  
Gene Transcripts ◽  
Protein Components ◽  
Intron Removal ◽  
Nuclear Ribonucleoprotein

Most protein-coding genes in eukaryotes are interrupted by non-coding intervening sequences (introns), which must be precisely removed from primary gene transcripts (pre-mRNAs) before translation of the message into protein. Intron removal by pre-mRNA splicing occurs in the nucleus and is catalysed by complex ribonucleoprotein machines called spliceosomes. These molecular machines consist of several small nuclear RNA molecules and their associated proteins [together termed snRNP (small nuclear ribonucleoprotein) particles], plus multiple accessory factors. Of particular interest are the U2, U5 and U6 snRNPs, which play crucial roles in the catalytic steps of splicing. In the present review, we summarize our current understanding of the role played by the protein components of the U5 snRNP in pre-mRNA splicing, which include some of the largest and most highly conserved nuclear proteins.

scholarly journals Identification of Novel Virulence-Associated Proteins Secreted to Xylem by Verticillium nonalfalfae During Colonization of Hop Plants

2016 ◽  
Vol 29 (5) ◽  
pp. 362-373 ◽  
Author(s):  
Marko Flajsman ◽  
Stanislav Mandelc ◽  
Sebastjan Radisek ◽  
Natasa Stajner ◽  
Jernej Jakse ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Xylem Sap ◽  
Hypothetical Protein ◽  
Secreted Proteins ◽  
In Planta ◽  
Fungal Virulence ◽  
Associated Proteins ◽  
Verticillium Nonalfalfae ◽  
Identification And Characterization

Plant pathogens employ various secreted proteins to suppress host immunity for their successful host colonization. Identification and characterization of pathogen-secreted proteins can contribute to an understanding of the pathogenicity mechanism and help in disease control. We used proteomics to search for proteins secreted to xylem by the vascular pathogen Verticillium nonalfalfae during colonization of hop plants. Three highly abundant fungal proteins were identified: two enzymes, α-N-arabinofuranosidase (VnaAbf4.216) and peroxidase (VnaPRX1.1277), and one small secreted hypothetical protein (VnaSSP4.2). These are the first secreted proteins so far identified in xylem sap following infection with Verticillium spp. VnaPRX1.1277, classified as a heme-containing peroxidase from Class II, similar to other Verticillium spp. lignin-degrading peroxidases, and VnaSSP4.2, a 14-kDa cysteine-containing protein with unknown function and with a close homolog in related V. alfalfae strains, were further examined. The in planta expression of VnaPRX1.1277 and VnaSSP4.2 genes increased with the progression of colonization, implicating their role in fungal virulence. Indeed, V. nonalfalfae deletion mutants of both genes exhibited attenuated virulence on hop plants, which returned to the level of the wild-type pathogenicity in the knockout complementation lines, supporting VnaPRX1.1277 and VnaSSP4.2 as virulence factors required to promote V. nonalfalfae colonization of hop plants.

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