SATB2 interacts with chromatin-remodeling molecules in differentiating cortical neurons.
During our search for developmental regulators of neuronal differentiation, we identified special AT-rich sequence-binding protein (SATB)2 that is specifically expressed in the developing rat neocortex and binds to AT-rich DNA elements. Here we investigated whether the regulatory function of SATB2 involves chromatin remodeling at the AT-rich DNA site. In-vitro and in-vivo assays using a DNA affinity pre-incubation specificity test of recognition and chromatin immunoprecipitation showed that SATB2 specifically binds to histone deacetylase 1 and metastasis-associated protein 2, members of the nucleosome-remodeling and histone deacetylase complex. Double immunohistochemistry showed that, in the developing rat neocortex, SATB2 is coexpressed with both proteins. Using a cell culture model, we showed that trichostatin A treatment, which blocks the activities of histone deacetylases, reverses the AT-rich dsDNA-dependent repressor effect of SATB2. These findings suggested that the molecular regulatory function of SATB2 involves modification of the chromatin structure. Semi-quantitative chromatin immunoprecipitation analysis of cortices from SATB2 mutant and wild-type animals indicated that, in the knock-out brains, SATB2 is replaced in the chromatin-remodeling complex by AU-rich element RNA binding protein 1, another AT-rich DNA binding protein also expressed in differentiating cortical neurons. These results suggested that an altered chromatin structure, due to the presence of different AT-rich DNA binding proteins in the chromatin-remodeling complex, may contribute to the developmental abnormalities observed in the SATB2 mutant animals. These findings also raised the interesting possibility that SATB2, along with other AT-rich DNA binding proteins, is involved in mediating epigenetic influences during cortical development.
Gyorgy
Andrea B
AB
Department of Anatomy, Physiology and Genetics, School of Medicine USU, Bethesda, MD 20814, USA.
Szemes
Marianna
M
de Juan Romero
Camino
C
Tarabykin
Victor
V
Agoston
Denes V
DV
D000818:Animals; D002454:Cell Differentiation / Q000235:genetics*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology* / Q000378:metabolism; D042002:Chromatin Assembly and Disassembly / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D044127:Epigenesis, Genetic; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases / Q000378:metabolism; D015151:Immunoblotting; D007150:Immunohistochemistry; D008716:Methionine Adenosyltransferase / Q000378:metabolism; D009474:Neurons / Q000166:cytology* / Q000378:metabolism*; D051381:Rats; D011922:Rats, Mutant Strains; D017207:Rats, Sprague-Dawley
D004268:DNA-Binding Proteins; C512846:Mat2a protein, rat; D008716:Methionine Adenosyltransferase; C515890:Hdac1 protein, rat; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases