Identifiers and Description

Gene Model Identifier

TTHERM_00823720

Standard Name

HHO1 (Histone H One )

Aliases

PreTt20442 | 141.m00099 | 3682.m00033

Description

Histone H1; macronuclear linker histone that associates with inter-nucleosomal DNA; lacks globular domain typical of linker histones; five phosphorylation

Genome Browser (Macronucleus)

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Genome Browser (Micronucleus)

GBrowse

Gene Ontology Annotations

Cellular Component

Biological Process

Domains

  • ( PF07554 ) Uncharacterised Sugar-binding Domain

Gene Expression Profile

  • Tetrahymena Functional Genomics Database:

Change in Gene Expression

TMHMM

TMHMM

Signal Peptide

Signal Peptide Present?: No
Presense Probability: 9.3%

TetraMine Data

TTHERM_00823720

WebApollo

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Tetrahymena Stock Center

No Data fetched for StockID

Homologs (v.2006 protein sequences)

SourceIdentifierScoreDescription
Tetrahymena borealisEI9_18157.18.001486403440551e-25hypothetical protein (164 aa)

General Information

Paragraph NoGene NameParagraph Text
8HHO1,
MLH1
The HHO1 gene encodes the macronuclear linker histone H1 protein; the MLH1 gene encodes a polyprotein comprising a set of four micronuclear linker histone proteins (alpha, beta, gamma, and delta) unrelated to Hho1p. Histone H1 and the MLH proteins are chromatin proteins that associate with the inter-nucleosomal (linker) DNA. T. thermophila has two nuclei, one of which is transcriptionally active (the macronucleus) and one that is silent during most of the life cycle (the micronucleus). Furthermore, the macronucleus undergoes amitosis, whereas the micronucleus undergoes typical mitosis. The fact that Hho1p and MLH proteins are found exclusively in the macronucleus and micronucleus, respectively, has led to studies of their function, or lack of function, in transcription regulation, mitosis, and amitosis. Surprisingly, an HHO1 knockout showed this gene to be non-essential; its main observable phenotype was an overall decondensation of macronuclear chromatin. MLH1 knockouts, which are also viable, showed a similar phenotype in the micronucleus.
9HHO1,
CDC2,
NgoA,
CYP1
HHO1 knockouts show no global increase or decrease in the amount of transcription in the cell; however, these same knockouts also show that Hho1p is important for the transcriptional regulation of individual genes in response to stimuli, such as starvation. The differential regulation of Hho1p by phosphorylation under vegetative growth and starvation conditions has been well studied. During vegetative growth, Hho1p is phosphorylated on five closely spaced residues, preventing it from interacting with chromatin, likely by interfering with its ability to bind DNA. Under these conditions, expression is increased for CDC2, a homolog of the cyclin dependent kinases responsible for histone H1 phosphorylation, possibly creating a positive feedback loop that promotes the cell cycle. During starvation conditions, Hho1p is dephosphorylated, allowing it to bind to chromatin. This stimulates the expression of some genes, including ngoA, and protease genes such as CYP1, while inhibiting expression of other genes, such as CDC2. This decrease in CDC2 expression may be responsible for cell cycle arrest during starvation.

Associated Literature

No Data fetched for Associated Literature

Sequences

>TTHERM_00823720(coding)
ATGGTTGTGTTATATGAAATTAATTCTTATAGATATAAAGAATCTTAGAAATTTTAATTC
GATGGATTGATTAAAGATATATAAAAACTTCCTCTTAGATATTTGATAAGAGAGAGATAA
ATCTTATTTGGAGAGGAGATTATCCAATCAGATTTCAGATTATTTTTAAGAGAAATTTTT
GAATTTGATATAAACCCATATCTAACGCGCGATATTATAATCTAATATACAAAATTAAAT
CGTTAAGAAAAAAACAAGAAAAAAAAACTAAAAAACAAATAATATAAAATGGCTCCCAGA
AGTTCAACTTCCAAGTCTGCTACCAGAGAAAAGAAGGACCACAAGAAGGCTCCCATCAAG
AAAGCCATCGCCAAGAAGGATACTAAGCCTACCCCCACCAAGGGCAAGGCTGCTTCTGCT
TCCACCACCCCCGTCAAGAAGGATGTCACCCCCGTCAAGGCTGATACCAAGAAGAAGATC
CACAAAACCAAAACCATGAAGGAAACCGTCAGCGATGCCAAGAAGACCGTTCACGCTGCT
GCTGGTGATAAGAAGCTCTCTAAAAAGAGACCCGCTAAGGAAGCTGCTAAGAAGGCTATC
AACCCTGGTAAGAAGGCTGCTGCTTAACCCAAGAGCACCAAGAAGGAAGTTAAGAAGGAC
AATAAGACTGCCAAGAAGGAAACCAAGAAAGATCATAAGCCCGCTAAGAAGGAAGCTAAG
AAGGAAACCAAGCCTGCCAAGAAAGATGCCAAGAAGAGCTCCAAGCCTGCCAAGAAGAAC
TGA


>TTHERM_00823720(protein)
MVVLYEINSYRYKESQKFQFDGLIKDIQKLPLRYLIRERQILFGEEIIQSDFRLFLREIF
EFDINPYLTRDIIIQYTKLNRQEKNKKKKLKNKQYKMAPRSSTSKSATREKKDHKKAPIK
KAIAKKDTKPTPTKGKAASASTTPVKKDVTPVKADTKKKIHKTKTMKETVSDAKKTVHAA
AGDKKLSKKRPAKEAAKKAINPGKKAAAQPKSTKKEVKKDNKTAKKETKKDHKPAKKEAK
KETKPAKKDAKKSSKPAKKN


>TTHERM_00823720(gene)
ATGGTTGTGTTATATGAAATTAATTCTTATAGATATAAAGAATCTTAGAAATTTTAATTC
GATGGATTGATTAAAGATATATAAAAACTTCCTCTTAGATATTTGATAAGAGAGAGATAA
ATCTTATTTGGAGAGGAGATTATCCAATCAGATTTCAGATTATTTTTAAGAGAAATTTTT
GAATTTGATATAAACCCATATCTAACGCGCGATATTATAATCTAATATACAAAATTAAAT
CGTTAAGAAAAAAACAAGAAAAAAAAACTAAAAAACAAATAATATAAAATGGCTCCCAGA
AGTTCAACTTCCAAGTCTGCTACCAGAGAAAAGAAGGACCACAAGAAGGCTCCCATCAAG
AAAGCCATCGCCAAGAAGGATACTAAGCCTACCCCCACCAAGGGCAAGGCTGCTTCTGCT
TCCACCACCCCCGTCAAGAAGGATGTCACCCCCGTCAAGGCTGATACCAAGAAGAAGATC
CACAAAACCAAAACCATGAAGGAAACCGTCAGCGTAAGAATTTAACGATTTGTTTCTACT
ATTTTCATTAAATAAATTCAAAATAGAATTTTTAATTACTAAATACTTTCTCCTCCTTTG
GTTATTTATTGAAGTTTCTACTATTTTTAAGAAACATATTTTAATAGTTCTACACTTTTT
TTCTCACTAAAAGAGAGTTAAAAAGTAGAATGAATGAATTAATACAAATATTATTGGGAA
AAACGTTTTATTCATTTTATTGAAAATATCTTTAATTTAAAAATTAGGATGCCAAGAAGA
CCGTTCACGCTGCTGCTGGTGATAAGAAGCTCTCTAAAAAGAGACCCGCTAAGGAAGCTG
CTAAGAAGGCTATCAACCCTGGTAAGAAGGCTGCTGCTTAACCCAAGAGCACCAAGAAGG
AAGTTAAGAAGGACAATAAGACTGCCAAGAAGGAAACCAAGAAAGATCATAAGCCCGCTA
AGAAGGAAGCTAAGAAGGAAACCAAGCCTGCCAAGAAAGATGCCAAGAAGAGCTCCAAGC
CTGCCAAGAAGAACTGA