Upregulation of class II histone deacetylases mRNA during neural differentiation of cultured rat hippocampal progenitor cells.

We studied the expression of histone deacetylases (HDACs 1-10) mRNAs during early differentiation of cultured rat hippocampal progenitor cells using Northern blot analysis. Embryonic rat hippocampal progenitors were kept proliferating and undifferentiated (neurospheres) in the presence of mitogens and induced to stop proliferation and to differentiate into neurons and astrocytes by mitogen removal. We found two- to four-fold elevated levels of mRNAs for HDAC 5, 6, 7 and 9 in early differentiation times in comparison with proliferating neurospheres while mRNA levels for HDAC 1, 2 and 3 did not change significantly. Interestingly, the upregulated HDACs all belong to class II of histone deacetylases. mRNAs for HDAC 4, 8 and 10 were not detectable by Northern analysis. We suggest that the changes in HDAC mRNA expression levels might be connected with chromatin rearrangement during neural differentiation.