Lander and Bernstein similarly determined specific histone modifications that distinguish actively expressed genes, genes poised for expression, and repressed genes in different kinds of cells.
It is possible that an actively expressed gene can suppress the expression of a close-by gene, especially a weakly expressed gene.
Similarly, specific histone modifications may distinguish actively expressed genes from genes that are poised for expression or genes that are repressed in different kinds of cells.
For example, in bovine blastocysts, sex determines the expression levels of one-third of all actively expressed genes [ 107].
In other words, CSR-1 activity may exclude deposition of H3K9me2 marks at actively expressed chromatin regions.
PD-1 is actively expressed on the cell surface during the activation of T and B cells.
It is actively expressed in response to infections, and upregulation of its expression is accompanied by an increase in the release of its soluble form (sTREM-1) [ 25].
For example, certain histone modifications distinguish actively expressed regions of the genome from regions that are not highly expressed.
"ExxonMobil condemns human rights violations in any form and has actively expressed these views to governments and others around the world," the spokesman said.
Furthermore, not all genes on the X chromosome are inactivated; a small number escape modification and remain actively expressed from both X chromosomes in the cell.
Altogether Dr. Dulac found 347 genes where either the mother's or the father's copy was more actively expressed in certain regions of the brain.
