Epigenetics and transcriptional control in African trypanosomes.

@article{Rudenko2010EpigeneticsAT,
  title={Epigenetics and transcriptional control in African trypanosomes.},
  author={Gloria Rudenko},
  journal={Essays in biochemistry},
  year={2010},
  volume={48 1},
  pages={
          201-19
        }
}
  • G. Rudenko
  • Published 20 September 2010
  • Biology
  • Essays in biochemistry
The African trypanosome Trypanosoma brucei is a unicellular parasite which causes African sleeping sickness. Transcription in African trypanosomes displays some unusual features, as most of the trypanosome genome is transcribed as extensive polycistronic RNA Pol II (polymerase II) transcription units that are not transcriptionally regulated. In addition, RNA Pol I is used for transcription of a small subset of protein coding genes in addition to the rDNA (ribosomal DNA). These Pol I-transcribed… 
View on PubMed
essays.biochemistry.org
48 Citations
Highly Influential Citations
2
Background Citations
25
Methods Citations
1
Results Citations
1

Figures from this paper

48 Citations

Citation Type

Citation Type

Epigenetic Regulation of Transcription in Trypanosomatid Protozoa
TLDR
The current knowledge on epigenetic control of transcription by all three RNA polymerases in the Trypanosomatids group of early-diverged eukaryotes is reviewed.
The epigenome of Trypanosoma brucei: a regulatory interface to an unconventional transcriptional machine.
TDP1 is an HMG chromatin protein facilitating RNA polymerase I transcription in African trypanosomes
TLDR
It is shown that the TDP1 architectural chromatin protein is an essential high mobility group box (HMGB) protein facilitating Pol I transcription in Trypanosoma brucei and has a mutually exclusive relationship with histones on actively transcribed pol I transcription units, providing insight into howPol I transcription is controlled.
Investigation of the role of the NLP and TDP1 chromatin associated proteins in transcription control in Trypanosoma brucei
TLDR
The high mobility group B (HMGB) protein family constitutes a major abundant class of non-histone chromatin associated DNA-binding proteins which play a role in chromatin architecture in a wide range of eukaryotes.
Maf1 is a negative regulator of transcription in Trypanosoma brucei
TLDR
Analysis of Maf1 in the parasitic protozoa Trypanosoma brucei revealed that TbMaf1 regulates Pol I transcription of procyclin gene and Pol II transcription of SL RNA genes, and nuclear run‐on and chromatin immunoprecipitation analyses demonstrated that it represses Pol III transcription of tRNA and U2 snRNA genes by associating with their promoters.
Histone H1 Plays a Role in Heterochromatin Formation and VSG Expression Site Silencing in Trypanosoma brucei
TLDR
It is shown that histone H1 proteins play a key role in the maintenance of higher order chromatin structure in bloodstream form T. brucei and H1 plays a role in downregulating silent ESs, arguing that H1-mediated chromatin functions in antigenic variation in T. Brucei.
Essential bromodomain TcBDF2 as a drug target against Chagas disease
TLDR
Overexpression of TcBDF2 diminished epimastigote replication, and some processes involved in pathogenesis were altered in these parasites, such as infection of mammalian cells, replication of amastigotes, and the number of trypomastsigotes released from host cells.
Mono-allelic VSG expression by RNA polymerase I in Trypanosoma brucei: expression site control from both ends?
Identification of the ISWI Chromatin Remodeling Complex of the Early Branching Eukaryote Trypanosoma brucei*
TLDR
The early branching eukaryote Trypanosoma brucei appears to have a single major ISWI complex, with reduced complexity of ISWI regulation and the presence of novel ISWI partners, which highlights the early divergence of trypanosomes in evolution.
Depletion of Trypanosome CTR9 Leads to Gene Expression Defects
TLDR
The results of tandem affinity purification suggested that trypanosome CTR9 associates with homologues of Leo1 and Cdc73; genes encoding homologue of Rtf1 and Paf1 were not found.
...
1
2
3
4
5
...

References

SHOWING 1-10 OF 100 REFERENCES
Active VSG Expression Sites in Trypanosoma brucei Are Depleted of Nucleosomes
ABSTRACT African trypanosomes regulate transcription differently from other eukaryotes. Most of the trypanosome genome is constitutively transcribed by RNA polymerase II (Pol II) as large…
Nucleosomes Are Depleted at the VSG Expression Site Transcribed by RNA Polymerase I in African Trypanosomes
TLDR
Observations that there are fewer nucleosomes at the active BES and that these are irregularly spaced compared to silent BESs provide new insight on antigenic variation by showing that chromatin remodeling is an intrinsic feature of BES regulation.
Repression of polymerase I‐mediated gene expression at Trypanosoma brucei telomeres
TLDR
It is shown that artificially seeded de novo telomeres repress Pol I‐dependent gene expression in mammalian bloodstream and insect life‐cycle stages of T. brucei and indicates that an enhanced, developmental stage‐specific repression mechanism controls antigenic variation.
Nuclear repositioning of the VSG promoter during developmental silencing in Trypanosoma brucei
TLDR
This work proposes a model whereby the VSG expression site pol I promoter is selectively targeted by temporal nuclear repositioning during developmental silencing, and reports that nonmutually exclusive procyclin genes are located at the nucleolar periphery.
A pol I transcriptional body associated with VSG mono-allelic expression in Trypanosoma brucei
TLDR
It is proposed that the recruitment of a single expression site and the concomitant exclusion of inactive loci from a discrete transcriptional body define the mechanism responsible for VSG mono-allelic expression.
The PARP promoter of Trypanosoma brucei is developmentally regulated in a chromosomal context.
TLDR
African trypanosomes are extracellular protozoan parasites that are transmitted from one mammalian host to the next by tsetse flies, and post-transcriptional mechanisms are mainly responsible for PARP mRNA regulation but results of nuclear run-on experiments suggested that transcription might also be regulated.
A sirtuin in the African trypanosome is involved in both DNA repair and telomeric gene silencing but is not required for antigenic variation
TLDR
It is shown that, in the mammalian‐infective bloodstream‐stage of the African trypanosome, Trypanosoma brucei, SIR2rp1 localizes to the nucleus while SIR1rp2 and SIR3rp3 are both mitochondrial proteins.
VSG gene expression site control in insect form Trypanosoma brucei.
TLDR
It is concluded that the down‐regulation of VSG gene expression site promoters in insect form trypanosomes is affected by both the DNA sequence of the promoter and the genomic context in which it resides.
Telomere length regulation and transcriptional silencing in KU80-deficient Trypanosoma brucei.
TLDR
Using real-time PCR, it is demonstrated that the expression of several different VSG genes remains tightly regulated in tbKU80-deficient bloodstream-form cell lines, suggesting that VSG transcription profiles do not change in these cells.
A Histone Methyltransferase Modulates Antigenic Variation in African Trypanosomes
TLDR
It is concluded that DOT1B is required to maintain strict VSG silencing and to ensure rapid transcriptional VSG switching, demonstrating that epigenetics plays an important role in regulating antigenic variation in T. brucei.
...
1
2
3
4
5
...