An abundant nucleolar phosphoprotein is associated with ribosomal DNA in Tetrahymena macronuclei.

McGrath, Kathleen E.; Smothers, James; Dadd, Christopher A.; Madireddi, Malavi T.; Gorovsky, Martin A.; Allis, C. David

doi:10.1091/mbc.8.1.97

Cited by 23 publications

(16 citation statements)

References 47 publications

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“…For example, three phosphorylation sites (S-43/S-45/T-47) of T. thermophila linker histone H1 were identified in this study, which is consistent with previous research (6). In agreement with previous predictions, the phosphorylation of S-231 in T. thermophila macronuclear phosphoprotein Nopp52 was also identified in this study (47).…”

Section: Establishment Of the T Thermophila Phosphoproteome-insupporting

confidence: 93%

Phosphoproteomic Analysis of Protein Phosphorylation Networks in Tetrahymena thermophila, a Model Single-celled Organism

Tian

Chen

Xiong

et al. 2014

Molecular & Cellular Proteomics

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Tetrahymena thermophila is a widely used unicellular eukaryotic model organism in biological research and contains more than 1000 protein kinases and phosphatases with specificity for Ser/Thr/Tyr residues. However, only a few dozen phosphorylation sites in T. thermophila are known, presenting a major obstacle to further understanding of the regulatory roles of reversible phosphorylation in this organism. In this study, we used high-accuracy mass-spectrometry-based proteomics to conduct global and site-specific phosphoproteome profiling of T. thermophila. In total, 1384 phosphopeptides and 2238 phosphorylation sites from 1008 T. thermophila proteins were identified through the combined use of peptide prefractionation, TiO 2 enrichment, and two-dimensional LC-MS/MS analysis. The identified phosphoproteins are implicated in the regulation of various biological processes such as transport, gene expression, and mRNA metabolic process. Moreover, integrated analysis of the T. thermophila phosphoproteome and gene network revealed the potential biological functions of many previously unannotated proteins and predicted some putative kinase-substrate pairs. Our data provide the first global survey of phosphorylation in T. thermophila using a phosphoproteomic approach and suggest a wideranging regulatory scope of this modification. The provided dataset is a valuable resource for the future understanding of signaling pathways in this important model organism. Molecular & Cellular

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Section: Establishment Of the T Thermophila Phosphoproteome-insupporting

confidence: 93%

Phosphoproteomic Analysis of Protein Phosphorylation Networks in Tetrahymena thermophila, a Model Single-celled Organism

Tian

Chen

Xiong

et al. 2014

Molecular & Cellular Proteomics

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“…2b). This arrangement of alternating basic/acidic regions has also been described for the nucleolar proteins nucleolin, NSR1, NpI46, Nopp140, Nopp52 and B23/nucleophosmin (Dingwall et al 1987;Lapeyre et al 1987;Lee et al 1991;Meier and Blobel 1992;Shan et al 1994;McGrath et al 1997). Within ASE-1, starting at amino acid 145, a putative glycine-, arginine-, and phenylalanine-rich (GRF) region can be found (9/19 amino acids or 47%).…”

Section: Cloning Sequencing and Analysissupporting

confidence: 54%

ASE-1: a novel protein of the fibrillar centres of the nucleolus and nucleolus organizer region of mitotic chromosomes

et al. 1997

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A novel nucleolar component has been identified and cloned using a human autoimmune serum. This antigen, as inferred from the cDNA sequence, is an Mr 55000 protein. Immuno blot analysis, however, of both the native protein and the in vitro translation products of the cDNA showed that they migrate on SDS-PAGE at an apparent molecular mass of 90000 A BLAST search using the cDNA sequence indicated that it is in an antisense orientation to and overlaps the gene of the DNA repair enzyme ERCC-1. An open reading frame, without a translational start site, had been observed by others in this region of the chromosome 19 (19q13.3) and the putative protein was termed ASE-1 (Anti-Sense to ERCC-1). Our cDNA is a full-length equivalent of that open reading frame. ASE-1 was found to contain two domains that are present in a number of nucleolar specific proteins originating from a variety of organisms: a glycine-, arginine- and phenylalanine-rich putative nucleotide interaction domain and an alternating basic/acidic region. Indirect immunofluorescence analysis using antibodies generated to cloned regions of ASE-1 indicated that this protein occurs at the fibrillar centres of the nucleolus in interphase, the putative sites of rDNA transcription, and during cell division it is localized to the nucleolus organizer regions of the chromosomes. ASE-1 co-localises with the RNA polymerase I transcription initiation factor UBF/NOR-90 throughout all stages of the cell cycle and these two proteins associate with each other in vitro.

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“…7C to E) suggests a Twi1p-independent function in late development after pair separation (ϳ12 h postmixing). The appearance of these Wag1 bodies is accompanied by Twi1p disappearance from the new Mac and the formation of nucleoli, which are marked by fibrillarin and Nopp52 (32,44). DNA elimination structures and Nopp52 do not colocalize in the new Macs (44), and we show that Wag1p bodies do not colocalize with nucleoli or with DNA elimination structures ( Fig.…”

Section: Discussionmentioning

confidence: 77%

Two GW Repeat Proteins Interact with Tetrahymena thermophila Argonaute and Promote Genome Rearrangement

Bednenko

Noto

DeSouza

et al. 2009

Molecular and Cellular Biology

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In conjugating Tetrahymena thermophila, massive DNA elimination occurs upon the development of the new somatic genome from the germ line genome. Small, ϳ28-nucleotide scan RNAs (scnRNAs) and Twi1p, an Argonaute family member, mediate H3K27me3 and H3K9me3 histone H3 modifications, which lead to heterochromatin formation and the excision of the heterochromatinized germ line-limited sequences. In our search for new factors involved in developmental DNA rearrangement, we identified two Twi1p-interacting proteins, Wag1p and CnjBp. Both proteins contain GW (glycine and tryptophan) repeats, which are characteristic of several Argonaute-interacting proteins in other organisms. Wag1p and CnjBp colocalize with Twi1p in the parental macronucleus early in conjugation and in the new developing macronucleus during later developmental stages. Around the time DNA elimination occurs, Wag1p forms multiple nuclear bodies in the developing macronuclei that do not colocalize with heterochromatic DNA elimination structures. Analyses of ⌬WAG1, ⌬CnjB, and double ⌬WAG1 ⌬CnjB knockout strains revealed that WAG1 and CnjB genes need to be deleted together to inhibit the downregulation of specific scnRNAs, the formation of DNA elimination structures, and DNA excision. Thus, Wag1p and CnjBp are two novel players with overlapping functions in RNA interference-mediated genome rearrangement in Tetrahymena.

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An abundant nucleolar phosphoprotein is associated with ribosomal DNA in Tetrahymena macronuclei.

Cited by 23 publications

References 47 publications

Phosphoproteomic Analysis of Protein Phosphorylation Networks in Tetrahymena thermophila, a Model Single-celled Organism

Phosphoproteomic Analysis of Protein Phosphorylation Networks in Tetrahymena thermophila, a Model Single-celled Organism

ASE-1: a novel protein of the fibrillar centres of the nucleolus and nucleolus organizer region of mitotic chromosomes

Two GW Repeat Proteins Interact with Tetrahymena thermophila Argonaute and Promote Genome Rearrangement

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