scholarly journals Site-specific methylation of adenine in the nuclear genome of a eucaryote, Tetrahymena thermophila

1986 ◽  
Vol 6 (7) ◽  
pp. 2364-2370
Author(s):  
G S Harrison ◽  
R C Findly ◽  
K M Karrer
Keyword(s):  
Heat Shock ◽  
Protein Gene ◽  
De Novo ◽  
Tetrahymena Thermophila ◽  
Nuclear Genome ◽  
Histone H4 ◽  
Ciliated Protozoan ◽  
Site Specific ◽  
Logarithmic Growth ◽  
I Gene

DNA in the polyploid macronucleus of the ciliated protozoan Tetrahymena thermophila contains the modified base N6-methyladenine. We identified two GATC sites which are methylated in most or all of the 45 copies of the macronuclear genome. One site is 2 kilobases 5' to the histone H4-I gene, and the other is 5 kilobases 3' to the 73-kilodalton heat shock protein gene. These sites are de novo methylated between 10 and 16 h after initiation of conjugation, during macronuclear anlage development. The methylation states of these two GATC sites and four other unmethylated GATC sites do not change in the DNA of cells cultured under conditions which change the activity of the genes, including logarithmic growth, starvation, and heat shock.

scholarly journals Site-specific methylation of adenine in the nuclear genome of a eucaryote, Tetrahymena thermophila.

1986 ◽  
Vol 6 (7) ◽  
pp. 2364-2370 ◽  
Author(s):  
G S Harrison ◽  
R C Findly ◽  
K M Karrer
Keyword(s):  
Heat Shock ◽  
Protein Gene ◽  
De Novo ◽  
Tetrahymena Thermophila ◽  
Nuclear Genome ◽  
Histone H4 ◽  
Ciliated Protozoan ◽  
Site Specific ◽  
Logarithmic Growth ◽  
I Gene

DNA in the polyploid macronucleus of the ciliated protozoan Tetrahymena thermophila contains the modified base N6-methyladenine. We identified two GATC sites which are methylated in most or all of the 45 copies of the macronuclear genome. One site is 2 kilobases 5' to the histone H4-I gene, and the other is 5 kilobases 3' to the 73-kilodalton heat shock protein gene. These sites are de novo methylated between 10 and 16 h after initiation of conjugation, during macronuclear anlage development. The methylation states of these two GATC sites and four other unmethylated GATC sites do not change in the DNA of cells cultured under conditions which change the activity of the genes, including logarithmic growth, starvation, and heat shock.

scholarly journals Formation of stable chromatin structures on the histone H4 gene during differentiation in Tetrahymena thermophila.

1986 ◽  
Vol 6 (8) ◽  
pp. 3014-3017 ◽  
Author(s):  
D S Pederson ◽  
K Shupe ◽  
G A Bannon ◽  
M A Gorovsky
Keyword(s):  
Chromatin Structure ◽  
Transcriptional Control ◽  
Tetrahymena Thermophila ◽  
Micrococcal Nuclease ◽  
Histone H4 ◽  
Hypersensitive Sites ◽  
Nuclear Differentiation ◽  
Histone Gene Transcription ◽  
The Relationship ◽  
I Gene

The relationship between chromatin structure and the transcriptional activity of the histone H4-I gene of Tetrahymena thermophila was explored. Indirect end-labeling studies demonstrated that major DNase I- and micrococcal nuclease-hypersensitive sites flank the active macronuclear genes but not the inactive micronuclear genes. Runon transcription experiments with isolated macronuclei indicated that histone gene transcription rates decreased when cells were starved. However, macronuclear nuclease-hypersensitive sites persisted upon starvation. Thus, one level of transcriptional control of the H4-I gene results in altered chromatin structure and is established during nuclear differentiation. The rate of transcription is also controlled, but not through hypersensitive site-associated structures.

Formation of stable chromatin structures on the histone H4 gene during differentiation in Tetrahymena thermophila

1986 ◽  
Vol 6 (8) ◽  
pp. 3014-3017
Author(s):  
D S Pederson ◽  
K Shupe ◽  
G A Bannon ◽  
M A Gorovsky
Keyword(s):  
Chromatin Structure ◽  
Transcriptional Control ◽  
Tetrahymena Thermophila ◽  
Micrococcal Nuclease ◽  
Histone H4 ◽  
Hypersensitive Sites ◽  
Nuclear Differentiation ◽  
Histone Gene Transcription ◽  
The Relationship ◽  
I Gene

The relationship between chromatin structure and the transcriptional activity of the histone H4-I gene of Tetrahymena thermophila was explored. Indirect end-labeling studies demonstrated that major DNase I- and micrococcal nuclease-hypersensitive sites flank the active macronuclear genes but not the inactive micronuclear genes. Runon transcription experiments with isolated macronuclei indicated that histone gene transcription rates decreased when cells were starved. However, macronuclear nuclease-hypersensitive sites persisted upon starvation. Thus, one level of transcriptional control of the H4-I gene results in altered chromatin structure and is established during nuclear differentiation. The rate of transcription is also controlled, but not through hypersensitive site-associated structures.

scholarly journals Autonomously Replicating Macronuclear DNA Pieces Are the Physical Basis of Genetic Coassortment Groups in Tetrahymena thermophila

Genetics ◽  
2000 ◽  
Vol 155 (3) ◽  
pp. 1119-1125
Author(s):  
Laura Wong ◽  
Lana Klionsky ◽  
Steve Wickert ◽  
Virginia Merriam ◽  
Eduardo Orias ◽  
...  
Keyword(s):  
Random Distribution ◽  
Tetrahymena Thermophila ◽  
Physical Basis ◽  
The Other ◽  
Site Specific ◽  
Phenotypic Assortment ◽  
Somatic Genome

Abstract The macronucleus of the ciliate Tetrahymena thermophila contains a fragmented somatic genome consisting of several hundred identifiable chromosome pieces. These pieces are generated by site-specific fragmentation of the germline chromosomes and most of them are represented at an average of 45 copies per macronucleus. In the course of successive divisions of an initially heterozygous macronucleus, the random distribution of alleles of loci carried on these copies eventually generates macronuclei that are pure for one allele or the other. This phenomenon is called phenotypic assortment. We have previously reported the existence of loci that assort together (coassort) and hypothesized that these loci reside on the same macronuclear piece. The work reported here provides new, rigorous genetic support for the hypothesis that macronuclear autonomously replicating chromosome pieces are the physical basis of coassortment groups. Thus, coassortment allows the mapping of the somatic genome by purely genetic means. The data also strongly suggest that the random distribution of alleles in the Tetrahymena macronucleus is due to the random distribution of the MAC chromosome pieces that carry them.

Sequence Characterization of Heat Shock Protein Gene ofCyclospora cayetanensisIsolates from Nepal, Mexico, and Peru

2013 ◽  
Vol 99 (2) ◽  
pp. 379-382 ◽  
Author(s):  
Irshad M. Sulaiman ◽  
Patricia Torres ◽  
Steven Simpson ◽  
Khalil Kerdahi ◽  
Ynes Ortega
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Protein Gene ◽  
Heat Shock Protein Gene ◽  
Sequence Characterization
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