Nextdoor is the private social network for your neighborhood. On Nextdoor, neighbors create private groups for their neighborhoods where they can ask questions, get to know one another, and exchange local advice and recommendations.
Up-regulation is a process that occurs within a cell triggered by a signal (originating internal or external to the cell), which results in increased expression of one or more genes and as a result the protein(s) encoded by those genes.
Each cell type is defined by its particular pattern of regulated gene expression. Cell differentiation is thus a transition of a cell from one cell type to another and it involves a switch from one pattern of gene expression to another.