Holocarboxylase synthetase acts as a biotin-independent transcriptional repressor interacting with HDAC1, HDAC2 and HDAC7.
In human cells, HCS catalyzes the biotinylation of biotin-dependent carboxylases and mediates the transcriptional control of genes involved in biotin metabolism through the activation of a cGMP-dependent signal transduction pathway. HCS also targets to the cell nucleus in association with lamin-B suggesting additional gene regulatory functions. Studies from our laboratory in Drosophila melanogaster showed that nuclear HCS is associated with heterochromatin bands enriched with the transcriptionally repressive mark histone 3 trimethylated at lysine 9. Further, HCS was shown to be recruited to the core promoter of the transcriptionally inactive hsp70 gene suggesting that it may participate in the repression of gene expression, although the mechanism involved remained elusive. In this work, we expressed HCS as a fusion protein with the DNA-binding domain of GAL4 to evaluate its effect on the transcription of a luciferase reporter gene. We show that HCS possesses transcriptional repressor activity in HepG2 cells. The transcriptional function of HCS was shown by in vitro pull down and in vivo co-immunoprecipitation assays to depend on its interaction with the histone deacetylases HDAC1, HDAC2 and HDAC7. We show further that HCS interaction with HDACs and its function in transcriptional repression is not affected by mutations impairing its biotin-ligase activity. We propose that nuclear HCS mediates events of transcriptional repression through a biotin-independent mechanism that involves its interaction with chromatin-modifying protein complexes that include histone deacetylases.
Programa de Investigación de Cáncer de Mama, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F. 04510, Mexico; Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F. 04510, Mexico.
Isis
I
Trujillo-Gonzalez
Programa de Investigación de Cáncer de Mama, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F. 04510, Mexico; Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F. 04510, Mexico.
Rafael
R
Cervantes-Roldan
Departamento de Biología Celular, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F. 04510, Mexico.
Alfonso
A
Gonzalez-Noriega
Departamento de Biología Celular, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F. 04510, Mexico.
Colette
C
Michalak
Programa de Investigación de Cáncer de Mama, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F. 04510, Mexico; Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F. 04510, Mexico.
Sandra
S
Reyes-Carmona
Programa de Investigación de Cáncer de Mama, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F. 04510, Mexico; Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F. 04510, Mexico.
Tonatiuh
T
Barrios-Garcia
Programa de Investigación de Cáncer de Mama, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F. 04510, Mexico; Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F. 04510, Mexico.
Ivan
I
Meneses-Morales
Programa de Investigación de Cáncer de Mama, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F. 04510, Mexico; Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F. 04510, Mexico. Electronic address: leon@biomedicas.unam.mx.
Alfonso
A
Leon-Del-Rio
D001710:Biotin / Q000378:metabolism; D019731:Carbon-Nitrogen Ligases / Q000235:genetics / Q000378:metabolism*; D002843:Chromatin; D004268:DNA-Binding Proteins / Q000378:metabolism; D029721:Drosophila Proteins / Q000378:metabolism; D056945:Hep G2 Cells; D006570:Heterochromatin / Q000235:genetics; D056284:Histone Deacetylase 1 / Q000235:genetics* / Q000378:metabolism; D056464:Histone Deacetylase 2 / Q000235:genetics* / Q000378:metabolism; D006655:Histone Deacetylases / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic
D002843:Chromatin; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; C557617:GAL4 protein, Drosophila; D006570:Heterochromatin; D014157:Transcription Factors; D001710:Biotin; C543273:HDAC7 protein, human; D056284:Histone Deacetylase 1; D056464:Histone Deacetylase 2; D006655:Histone Deacetylases; D019731:Carbon-Nitrogen Ligases; C023312:holocarboxylase synthetases
Biotin-ligase; H3K9met3; Histone deacetylases; Holocarboxylase synthetase; Moonlighting enzyme; Transcriptional repression