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Ty3 Retrotransposon Hijacks Mating Yeast RNA Processing Bodies to Infect New Genomes.

Bilanchone V, Clemens K, Kaake R, Dawson AR, Matheos D, Nagashima K, Sitlani P, Patterson K, Chang I, Huang L, Sandmeyer S - PLoS Genet. (2015)

Bottom Line: Components of RNA processing bodies including DEAD box helicases Dhh1/DDX6 and Ded1/DDX3, Sm-like protein Lsm1, decapping protein Dcp2, and 5' to 3' exonuclease Xrn1 were among the proteins identified.These proteins associated with Ty3 proteins and RNA, and were required for formation of Ty3 VLP retrosome assembly factories and for retrotransposition.Specifically, Dhh1/DDX6 was required for normal levels of Ty3 genomic RNA, and Lsm1 and Xrn1 were required for association of Ty3 protein and RNA into retrosomes.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Chemistry, University of California, Irvine, Irvine, California, United States of America.

ABSTRACT
Retrotransposition of the budding yeast long terminal repeat retrotransposon Ty3 is activated during mating. In this study, proteins that associate with Ty3 Gag3 capsid protein during virus-like particle (VLP) assembly were identified by mass spectrometry and screened for roles in mating-stimulated retrotransposition. Components of RNA processing bodies including DEAD box helicases Dhh1/DDX6 and Ded1/DDX3, Sm-like protein Lsm1, decapping protein Dcp2, and 5' to 3' exonuclease Xrn1 were among the proteins identified. These proteins associated with Ty3 proteins and RNA, and were required for formation of Ty3 VLP retrosome assembly factories and for retrotransposition. Specifically, Dhh1/DDX6 was required for normal levels of Ty3 genomic RNA, and Lsm1 and Xrn1 were required for association of Ty3 protein and RNA into retrosomes. This role for components of RNA processing bodies in promoting VLP assembly and retrotransposition during mating in a yeast that lacks RNA interference, contrasts with roles proposed for orthologous components in animal germ cell ribonucleoprotein granules in turnover and epigenetic suppression of retrotransposon RNAs.

No MeSH data available.


Related in: MedlinePlus

Ty3 expression effects on mating efficiency.Equal numbers of cells of each mating type either lacking Ty3 elements, or expressing Ty3 under the native promoter were mated for the time indicated. Mating efficiency (% mating) was determined as described Materials and Methods. (A) Yeast cells of two mating types fuse to form diploids. Mating efficiency in the presence and absence of endogenous Ty3 elements. (B) Mating efficiency of WT strains [BY4741 (MATa) and BY4742 (MATα); two endogenous Ty3 elements] and Ty3Δ strains [yVB1913 (MATa) and yDM1456 (MATα); BY4741 background with Ty3 elements deleted]. (C) Mating efficiency in the presence and absence of high-copy Ty3. Mating of Ty3Δ strains (yVB1672 (MATa) and yVB1926 (MATα); BY4741 background with Ty3 elements deleted and replaced by loxP) transformed with either a high-copy-number plasmid containing Ty3 (pDM3194) or a plasmid control (pYES2.0).
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pgen.1005528.g005: Ty3 expression effects on mating efficiency.Equal numbers of cells of each mating type either lacking Ty3 elements, or expressing Ty3 under the native promoter were mated for the time indicated. Mating efficiency (% mating) was determined as described Materials and Methods. (A) Yeast cells of two mating types fuse to form diploids. Mating efficiency in the presence and absence of endogenous Ty3 elements. (B) Mating efficiency of WT strains [BY4741 (MATa) and BY4742 (MATα); two endogenous Ty3 elements] and Ty3Δ strains [yVB1913 (MATa) and yDM1456 (MATα); BY4741 background with Ty3 elements deleted]. (C) Mating efficiency in the presence and absence of high-copy Ty3. Mating of Ty3Δ strains (yVB1672 (MATa) and yVB1926 (MATα); BY4741 background with Ty3 elements deleted and replaced by loxP) transformed with either a high-copy-number plasmid containing Ty3 (pDM3194) or a plasmid control (pYES2.0).

Mentions: Yeast PB segregate preferentially into daughter buds [69]. Furthermore, maternal RNA granules in metazoans, affect segregation of important RNAs in subsequent cell divisions. The observation that Ty3 contributes to PB formation suggested that mating might be influenced, either positively or negatively, in Ty3-populated strains. We therefore constructed derivatives of Ty3(WT) and Ty3Δ strains with appropriate nutritional markers to allow selection of diploid cells (see Materials and Methods). These strains were mixed and concentrated onto filters to promote mating for 1.5 or 2.5 h. Mated cells were spread onto double drop-out medium to select for diploid prototrophs with complementing nutritional markers. Mating efficiency at 1.5 h and 2.5 h was similar in Ty3(WT) and Ty3Δ strains (Fig 5A and 5B). To test whether a higher level of Ty3 expression produced an effect, the experiment was performed in the Ty3Δ background in the presence and absence of a high-copy-number plasmid from which Ty3 was expressed under the native promoter. In this context, Ty3 expression slightly reduced average mating efficiency at 3.5 h, but given the variation within the experiment this difference was not significant (Ty3Δ+pTy3 = 42.5±5.0% (mean ± SD) versus Ty3Δ+vector = 49.5±3.0%, p = 0.052) (Fig 5C).


Ty3 Retrotransposon Hijacks Mating Yeast RNA Processing Bodies to Infect New Genomes.

Bilanchone V, Clemens K, Kaake R, Dawson AR, Matheos D, Nagashima K, Sitlani P, Patterson K, Chang I, Huang L, Sandmeyer S - PLoS Genet. (2015)

Ty3 expression effects on mating efficiency.Equal numbers of cells of each mating type either lacking Ty3 elements, or expressing Ty3 under the native promoter were mated for the time indicated. Mating efficiency (% mating) was determined as described Materials and Methods. (A) Yeast cells of two mating types fuse to form diploids. Mating efficiency in the presence and absence of endogenous Ty3 elements. (B) Mating efficiency of WT strains [BY4741 (MATa) and BY4742 (MATα); two endogenous Ty3 elements] and Ty3Δ strains [yVB1913 (MATa) and yDM1456 (MATα); BY4741 background with Ty3 elements deleted]. (C) Mating efficiency in the presence and absence of high-copy Ty3. Mating of Ty3Δ strains (yVB1672 (MATa) and yVB1926 (MATα); BY4741 background with Ty3 elements deleted and replaced by loxP) transformed with either a high-copy-number plasmid containing Ty3 (pDM3194) or a plasmid control (pYES2.0).
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pgen.1005528.g005: Ty3 expression effects on mating efficiency.Equal numbers of cells of each mating type either lacking Ty3 elements, or expressing Ty3 under the native promoter were mated for the time indicated. Mating efficiency (% mating) was determined as described Materials and Methods. (A) Yeast cells of two mating types fuse to form diploids. Mating efficiency in the presence and absence of endogenous Ty3 elements. (B) Mating efficiency of WT strains [BY4741 (MATa) and BY4742 (MATα); two endogenous Ty3 elements] and Ty3Δ strains [yVB1913 (MATa) and yDM1456 (MATα); BY4741 background with Ty3 elements deleted]. (C) Mating efficiency in the presence and absence of high-copy Ty3. Mating of Ty3Δ strains (yVB1672 (MATa) and yVB1926 (MATα); BY4741 background with Ty3 elements deleted and replaced by loxP) transformed with either a high-copy-number plasmid containing Ty3 (pDM3194) or a plasmid control (pYES2.0).
Mentions: Yeast PB segregate preferentially into daughter buds [69]. Furthermore, maternal RNA granules in metazoans, affect segregation of important RNAs in subsequent cell divisions. The observation that Ty3 contributes to PB formation suggested that mating might be influenced, either positively or negatively, in Ty3-populated strains. We therefore constructed derivatives of Ty3(WT) and Ty3Δ strains with appropriate nutritional markers to allow selection of diploid cells (see Materials and Methods). These strains were mixed and concentrated onto filters to promote mating for 1.5 or 2.5 h. Mated cells were spread onto double drop-out medium to select for diploid prototrophs with complementing nutritional markers. Mating efficiency at 1.5 h and 2.5 h was similar in Ty3(WT) and Ty3Δ strains (Fig 5A and 5B). To test whether a higher level of Ty3 expression produced an effect, the experiment was performed in the Ty3Δ background in the presence and absence of a high-copy-number plasmid from which Ty3 was expressed under the native promoter. In this context, Ty3 expression slightly reduced average mating efficiency at 3.5 h, but given the variation within the experiment this difference was not significant (Ty3Δ+pTy3 = 42.5±5.0% (mean ± SD) versus Ty3Δ+vector = 49.5±3.0%, p = 0.052) (Fig 5C).

Bottom Line: Components of RNA processing bodies including DEAD box helicases Dhh1/DDX6 and Ded1/DDX3, Sm-like protein Lsm1, decapping protein Dcp2, and 5' to 3' exonuclease Xrn1 were among the proteins identified.These proteins associated with Ty3 proteins and RNA, and were required for formation of Ty3 VLP retrosome assembly factories and for retrotransposition.Specifically, Dhh1/DDX6 was required for normal levels of Ty3 genomic RNA, and Lsm1 and Xrn1 were required for association of Ty3 protein and RNA into retrosomes.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Chemistry, University of California, Irvine, Irvine, California, United States of America.

ABSTRACT
Retrotransposition of the budding yeast long terminal repeat retrotransposon Ty3 is activated during mating. In this study, proteins that associate with Ty3 Gag3 capsid protein during virus-like particle (VLP) assembly were identified by mass spectrometry and screened for roles in mating-stimulated retrotransposition. Components of RNA processing bodies including DEAD box helicases Dhh1/DDX6 and Ded1/DDX3, Sm-like protein Lsm1, decapping protein Dcp2, and 5' to 3' exonuclease Xrn1 were among the proteins identified. These proteins associated with Ty3 proteins and RNA, and were required for formation of Ty3 VLP retrosome assembly factories and for retrotransposition. Specifically, Dhh1/DDX6 was required for normal levels of Ty3 genomic RNA, and Lsm1 and Xrn1 were required for association of Ty3 protein and RNA into retrosomes. This role for components of RNA processing bodies in promoting VLP assembly and retrotransposition during mating in a yeast that lacks RNA interference, contrasts with roles proposed for orthologous components in animal germ cell ribonucleoprotein granules in turnover and epigenetic suppression of retrotransposon RNAs.

No MeSH data available.


Related in: MedlinePlus