RNAi and heterochromatin in plants and fission yeast / Prof. Robert Martienssen.

Format:

Video

Author/Creator:

Martienssen, Robert, author.

Series:

Henry Stewart talks

Language:

English

Subjects (All):

Epigenesis.

Physical Description:

1 videorecording (41 min., 20 sec.) : sound, color.

Place of Publication:

London : Henry Stewart Talks Ltd, [2016]

System Details:

video file

Summary:

Audio-visual presentation : Heterochromatin is composed of transposable elements (TEs) and related repeats ; heterochromatic gene silencing and TE-mediated silencing are related and may be important in large genomes ; tiling microarrays can be used to examine heterochromatic transcripts as well as DNA and histone modification ; small interfering RNA (siRNA) corresponds to transposons and repeats ; in plants TE siRNA depend on DNA methyltransferase MET1 and the SWI/SNF ATPase DDM1 which silence TEs via DNA and histone H3 lysine-9 (H3K9) methylation ; in fission yeast and plants centromeric repeats are transcribed on one strand but rapidly turned over by RNA interference (RNAi) ; RNAi of centromeric transcripts is required for transcriptional silencing of reporter genes ; RNA polymerase II, the Argonaute (RITS) and RNA dependent RNA polymerase (RDRC) complexes are associated with heterochromatin and required for silencing ; H3K9me2 depends on RNAi and on the Rik1-Clr4 complex ; Clr4 is the histone H3K9 dimethyltransferase ; Rik1 resembles both DNA and RNA binding proteins and is required for RNAi along with Clr4 ; LTR retrotransposon silencing depends on histone deacetylation and silences pericentromeric repeats in Arabidopsis in addition to RNAi.

Contents:

RNAi and heterochromatin: plants, fission yeast

Heterochromatic/transposon silencing

Transposons regulate genes via DNA methylation

Arabidopsis/fission yeast: gene silencing models

Arabidopsis chromosomes in meiosis

knob: model for high eukaryotic heterochromatin

Transposons/repeats/genes in heterochromatin

ddm1/met1 (ddm2) required for DNA methylation

Genomic tiling microarrays

ddm1 silences heterochromatin via methylation

ddm1 distinguishes genes from transposons

Some genes are methylated, but not by ddm1

siRNA, H3mK9/DNA methylation are correlated

24 nt transposon siRNA in met1/ddm1

The process of RNAi

RNAi genes dcl1/ago1 interact in Arabidopsis

Argonautes in Arabidopsis

The argonaute gene family

RNAi genes in S. pombe

Centromeric silencing requires RNAi

S. pombe centromeres are transcribed

Centromeric silencing: histone H3 methylation

Heterochromatin silences genes via RNAi

Gene silencing by dh repeats in S. pombe

Tf2 retrotransposons and nearby genes (wtf)

Centromeric silencing requires Pol II (Rpb2)

Centro. repeats transcr., not proces. in rpb2-m203

Rik1 required for H3K9 methylation and RNAi

Rik1 interacts with Dos1 (localized via Dos2)

RNAi and heterochromatin

RNAi required for chromosome segregation

Centromeres

Co-transcription of 106B LTR/satellite repeats

Centromere repeat siRNA require dcl3/rdr2/ddm1

Satellite transcripts localized in subnuclear dots

Tandem repeats and RNAi

Single copies cannot maintain siRNA

Tandem repeats maintain siRNA

Tandem repeat siRNA depends on met1/ddm1

Imprinted fwa gene regulated by ddm1/met1

fwa tandem repeats from SINE retrotransposon

Active heterochromatin is inherited from ddm1

Summary

Acknowledgments.

Notes:

Description based on publisher supplied metadata and other sources.

Retrieved April 9, 2024, from https://hstalks.com/bs/112/.