Two GW Repeat Proteins Interact with <i>Tetrahymena thermophila</i> Argonaute and Promote Genome Rearrangement

Bednenko, Janna; Noto, Tomoko; DeSouza, Leroi V.; Siu, Kin Wai Michael; Pearlman, Ronald E.; Mochizuki, Kazufumi; Gorovsky, Martin A.

doi:10.1128/mcb.00076-09

Cited by 44 publications

(35 citation statements)

References 51 publications

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“…The two micro- and two macronuclei developmental arrest point, which we observed upon mating Δ DRH1 mic strains, is a common phenotype described for several strains lacking genes required for developmentally programmed DNA rearrangements (Shieh and Chalker, 2013; Rexer and Chalker, 2007; Motl and Chalker, 2011; Malone et al, 2005; Horrell and Chalker, 2014; Noto et al, 2010; Mochizuki et al, 2002; Bednenko et al, 2009). To determine whether the developmental arrest observed upon loss of DRH1 expression was associated with defects in genome rearrangements, we assessed IES excision and chromosome breakage efficiency in Δ DRH1 mic strains post-conjugation.…”

Section: Resultssupporting

confidence: 53%

DRH1, a p68-related RNA helicase gene, is required for chromosome breakage in Tetrahymena

et al. 2016

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The p68 DEAD box helicases comprise a widely conserved protein family involved in a large range of biological processes including transcription, splicing and translation. The genome of the ciliate Tetrahymena thermophile encodes two p68-like helicases, Drh1p and Lia2p. We show that DRH1 is essential for growth and completion of development. In growing cells, Drh1p is excluded from the nucleus and accumulates near cortical basal bodies. In contrast, during sexual reproduction, this protein localizes to meiotic micronuclei, initially in punctate foci in regions where centromeres and telomeres are known to reside and later in post-zygotic differentiating somatic macronuclei. Differentiation of the macronuclear genome involves extensive DNA rearrangements including fragmentation of the five pairs of germline-derived chromosomes into 180 chromosomal sub-fragments that are stabilized by de novo telomere deletion. In addition, thousands of internal eliminated sequences (IESs) are excised from loci dispersed throughout the genome. Strains with DRH1 deleted from the germline nuclei, which do not express the protein during post-zygotic development, fail to fragment the developing macronuclear chromosomes. IES excision still occurs in the absence of DRH1 zygotic expression; thus, Drh1p is the first protein found to be specifically required for chromosome breakage but not DNA elimination.

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Section: Resultssupporting

confidence: 53%

DRH1, a p68-related RNA helicase gene, is required for chromosome breakage in Tetrahymena

et al. 2016

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“…None of the previously identified Twi1p-associated proteins are required for macronuclear localization of Twi1p (Aronica et al 2008, Bednenko et al 2009). To identify Twi1p-associated proteins involved in the macronuclear localization of Twi1p, FLAG-HA-Twi1p-containing complexes were isolated with milder lysis/washing conditions (see Materials and Methods) than those used in the previous studies.…”

Section: Resultsmentioning

confidence: 98%

The Tetrahymena Argonaute-Binding Protein Giw1p Directs a Mature Argonaute-siRNA Complex to the Nucleus

Noto

Kurth

Kataoka

et al. 2010

Cell

Self Cite

114

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Summary Emerging evidence suggests that RNAi-related processes act both in the cytoplasm and in the nucleus. However, the process by which the RNAi machinery is transported into the nucleus remains poorly understood. The Tetrahymena Argonaute protein Twi1p localizes to the nucleus and is crucial for small RNA-directed programmed DNA elimination. In this study, we identify Giw1p, which binds to Twi1p and is required for its nuclear localization. Further, the endoribonuclease (Slicer)-activity of Twi1p plays a vital role in the removal of one of the two strands of Twi1p-associated siRNAs, leading to a functionally mature Twi1p-siRNA complex. Slicer activity is also shown to be required for nuclear localization of Twi1p and for its association with Giw1p. These results suggest that Giw1p senses the state of Twi1p-associated siRNAs and selectively transports the mature Twi1p-siRNA complex into the nucleus.

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“…This result showed that JMJ1 RNAi knockdown partially inhibited the elimination of IES elements during conjugation and the effect might depend on the sequence or the genomic position of IESs. Differences in elimination efficiency of IESs were observed in several IES elimination mutants, including ⌬EMA1, ⌬HEN1, and ⌬WAG1/⌬CnjB strains (4,8,37).…”

Section: Resultsmentioning

confidence: 99%

Tetrahymena thermophila JMJD3 Homolog Regulates H3K27 Methylation and Nuclear Differentiation

Chung

Yao

2012

Eukaryot Cell

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Histone H3K27me3 modification is an important regulator for development and gene expression. In Tetrahymena thermophila, the complex chromatin dynamics of H3K27me3 marks during nuclear development suggested that an H3K27me3 demethylase might exist. Here, we report an H3K27me3 demethylase homolog, JMJ1, in Tetrahymena. During conjugation, JMJ1 expression is upregulated and the protein is localized first in the parental macronucleus and then in the new macronucleus. In conjugating cells, knockdown of JMJ1 expression resulted in a severe reduction in the production of progeny, suggesting that JMJ1 is essential for Tetrahymena conjugation. Furthermore, knockdown of JMJ1 resulted in increased H3K27 trimethylation in the new macronucleus and reduced transcription of genes related to DNA elimination, while the DNA elimination process was also partially blocked. Knockdown of the H3K27 methyltransferase EZL2 but not that of EZL1 partially restored progeny production in JMJ1-knockdown cells and reduced abnormal H3K27me3 accumulation in the new macronucleus. Taken together, these results demonstrate a critical role for JMJ1 in regulating H3K27me3 during conjugation and the importance of JMJ1 in regulating gene expression in the new macronucleus but not in regulating the formation of heterochromatin associated with programmed DNA deletion.

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

Cited by 44 publications

References 51 publications

DRH1, a p68-related RNA helicase gene, is required for chromosome breakage in Tetrahymena

DRH1, a p68-related RNA helicase gene, is required for chromosome breakage in Tetrahymena

The Tetrahymena Argonaute-Binding Protein Giw1p Directs a Mature Argonaute-siRNA Complex to the Nucleus

Tetrahymena thermophila JMJD3 Homolog Regulates H3K27 Methylation and Nuclear Differentiation

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