HHO1/YPL127C Summary Help

Standard Name HHO1 1
Systematic Name YPL127C
Feature Type ORF, Verified
Description Histone H1, linker histone with roles in meiosis and sporulation; decreasing levels early in sporulation may promote meiosis, and increasing levels during sporulation facilitate compaction of spore chromatin; binds to promoters and within genes in mature spores; may be recruited by Ume6p to promoter regions, contributing to transcriptional repression outside of meiosis; suppresses DNA repair involving homologous recombination (1, 2, 3, 4, 5, 6, 7, 8, 9 and see Summary Paragraph)
Name Description Histone H One 1
Chromosomal Location
ChrXVI:309604 to 308828 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Gene Ontology Annotations All HHO1 GO evidence and references
  View Computational GO annotations for HHO1
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 1 genes
Classical genetics
Large-scale survey
82 total interaction(s) for 70 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 21
  • Affinity Capture-RNA: 2
  • Affinity Capture-Western: 1
  • Biochemical Activity: 10
  • PCA: 11
  • Protein-peptide: 1

Genetic Interactions
  • Dosage Lethality: 1
  • Negative Genetic: 17
  • Phenotypic Suppression: 1
  • Positive Genetic: 8
  • Synthetic Growth Defect: 1
  • Synthetic Rescue: 8

Expression Summary
Length (a.a.) 258
Molecular Weight (Da) 27,803
Isoelectric Point (pI) 11.02
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrXVI:309604 to 308828 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Last Update Coordinates: 2011-02-03 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..777 309604..308828 2011-02-03 1996-07-31
Retrieve sequences
Analyze Sequence
S288C only
S288C vs. other species
S288C vs. other strains
External Links All Associated Seq | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000006048

About yeast nucleosomes...

Chromatin is composed of arrays of nucleosomes, with each nucleosome comprising an octamer formed by two copies each of the H2A-H2B and H3-H4 heterodimers (10). In Saccharomyces cerevisiae, each of the canonical histones is encoded by two genes: H2A by HTA1 and HTA2, H2B by HTB1 and HTB2, H3 by HHT1 and HHT2, and H4 by HHF1 and HHF2. The eight genes are organized into four pairs of divergently-transcribed loci: HTA1-HTB1 and HTA2-HTB2, each encoding histone proteins H2A and H2B; and HHT1-HHF1 and HHT2-HHF2, each encoding histone proteins H3 and H4. As a result of this redundancy, deletion of any one histone locus does not cause lethality (11). The H3-H4 protein dimers interact via a four-helix bundle at the H3 C-termini, and the H2A-H2B dimers bind to the resulting central H3-H4 tetramer via a similar four-helix bundle interaction between the H2B and H4 C-termini (12). Approximately 150 bp of duplex DNA is wound onto the histone octamer as two turns of a negative superhelix (13). A single copy of the linker histone H1 (encoded by HHO1) binds between the superhelices at the site of DNA entry and exit. In some nucleosomes, the histone variant H2A.Z (encoded by HTZ1) is substituted for the canonical H2A in a wide, but nonrandom, genomic distribution, enriched in promoter regions as compared to coding regions (14). The positioning of nucleosomes along chromatin has been implicated in the regulation of gene expression, since the packaging of DNA into nucleosomes affects sequence accessibility (15). Nucleosomes prevent many DNA-binding proteins from approaching their sites (16, 17, 18), whereas appropriately positioned nucleosomes can bring discontiguous DNA sequences into close proximity to promote transcription (19).

About the H1 linker histone...

Histone H1 is a linker histone that binds the outside of nucleosomes and modifies chromatin structure (20). Saccharomyces cerevisiae encodes a single H1 linker histone, Hho1p, which facilitates chromatin folding and contains two globular domains. The ability of Hho1p to facilitate chromatin folding is conferred by its lysine-rich C-terminal tail, and the globular domains appear to act as structure recognition modules, placing the lysine-rich C-terminal tail at a location on the nucleosome where it assumes a helical character when associated with the linker DNA. The C-terminal tail also effects partial charge neutralization of the DNA that connects adjacent nucleosomes (21, 22), which is assumed to stabilize chromatin fibers (10). Hho1p inhibits transcriptional silencing and reinforces the action of several types of barrier elements, which are DNA sequences that protect transcriptionally active euchromatic regions from encroachment by neighboring transcriptionally repressed heterochromatin (23).

The H1 histones form a large family of proteins, with eight isotypes identified in mammals, including five somatic isotypes (H1a-e), a testis-specific H1t, an oocyte-specific H1oo, and H1o, a replacement variant associated with terminally differentiated cell types and related to H5, which is found in nucleated avian erythrocytes (24). The canonical metazoan H1 contains a globular domain flanked by variable N-terminal and C-terminal regions (10). Some lower eukaryotes have atypical linker histones, such as Tetrahymena, in which H1 resembles an isolated C-terminal tail (25), or S. cerevisiae, where H1 contains the two globular domains mentioned above (6, 26).

Last updated: 2007-05-31 Contact SGD

References cited on this page View Complete Literature Guide for HHO1
1) Ushinsky SC, et al.  (1997) Histone H1 in Saccharomyces cerevisiae. Yeast 13(2):151-61
2) Patterton HG, et al.  (1998) The biochemical and phenotypic characterization of Hho1p, the putative linker histone H1 of Saccharomyces cerevisiae. J Biol Chem 273(13):7268-76
3) Puig S, et al.  (1999) Stochastic nucleosome positioning in a yeast chromatin region is not dependent on histone H1. Curr Microbiol 39(3):168-72
4) Escher D and Schaffner W  (1997) Gene activation at a distance and telomeric silencing are not affected by yeast histone H1. Mol Gen Genet 256(4):456-61
5) Hellauer K, et al.  (2001) Decreased expression of specific genes in yeast cells lacking histone H1. J Biol Chem 276(17):13587-92
6) Landsman D  (1996) Histone H1 in Saccharomyces cerevisiae: a double mystery solved? Trends Biochem Sci 21(8):287-8
7) Freidkin I and Katcoff DJ  (2001) Specific distribution of the Saccharomyces cerevisiae linker histone homolog HHO1p in the chromatin. Nucleic Acids Res 29(19):4043-51
8) Downs JA, et al.  (2003) Suppression of homologous recombination by the Saccharomyces cerevisiae linker histone. Mol Cell 11(6):1685-92
9) Bryant JM, et al.  (2012) The linker histone plays a dual role during gametogenesis in Saccharomyces cerevisiae. Mol Cell Biol 32(14):2771-83
10) Schafer G, et al.  (2005) The Saccharomyces cerevisiae linker histone Hho1p, with two globular domains, can simultaneously bind to two four-way junction DNA molecules. Biochemistry 44(50):16766-75
11) Dollard C, et al.  (1994) SPT10 and SPT21 are required for transcription of particular histone genes in Saccharomyces cerevisiae. Mol Cell Biol 14(8):5223-8
12) Luger K, et al.  (1997) Crystal structure of the nucleosome core particle at 2.8 A resolution. Nature 389(6648):251-60
13) Richmond TJ and Davey CA  (2003) The structure of DNA in the nucleosome core. Nature 423(6936):145-50
14) Li B, et al.  (2005) Preferential occupancy of histone variant H2AZ at inactive promoters influences local histone modifications and chromatin remodeling. Proc Natl Acad Sci U S A 102(51):18385-90
15) Yuan GC, et al.  (2005) Genome-scale identification of nucleosome positions in S. cerevisiae. Science 309(5734):626-30
16) Anderson JD and Widom J  (2000) Sequence and position-dependence of the equilibrium accessibility of nucleosomal DNA target sites. J Mol Biol 296(4):979-87
17) Wallrath LL, et al.  (1994) Architectural variations of inducible eukaryotic promoters: preset and remodeling chromatin structures. Bioessays 16(3):165-70
18) Venter U, et al.  (1994) A nucleosome precludes binding of the transcription factor Pho4 in vivo to a critical target site in the PHO5 promoter. EMBO J 13(20):4848-55
19) Stunkel W, et al.  (1997) A nucleosome positioned in the distal promoter region activates transcription of the human U6 gene. Mol Cell Biol 17(8):4397-405
20) Bustin M, et al.  (2005) The dynamics of histone H1 function in chromatin. Mol Cell 17(5):617-20
21) Allan J, et al.  (1982) Participation of core histone "tails" in the stabilization of the chromatin solenoid. J Cell Biol 93(2):285-97
22) Allan J, et al.  (1986) Roles of H1 domains in determining higher order chromatin structure and H1 location. J Mol Biol 187(4):591-601
23) Veron M, et al.  (2006) Histone H1 of Saccharomyces cerevisiae inhibits transcriptional silencing. Genetics 173(2):579-87
24) Parseghian MH and Hamkalo BA  (2001) A compendium of the histone H1 family of somatic subtypes: an elusive cast of characters and their characteristics. Biochem Cell Biol 79(3):289-304
25) Wu M, et al.  (1994) Four distinct and unusual linker proteins in a mitotically dividing nucleus are derived from a 71-kilodalton polyprotein, lack p34cdc2 sites, and contain protein kinase A sites. Mol Cell Biol 14(1):10-20
26) Ali T, et al.  (2004) Two homologous domains of similar structure but different stability in the yeast linker histone, Hho1p. J Mol Biol 338(1):139-48