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.
Cell differentiation is how generic embryonic cells become specialized cells. This occurs through a process called gene expression. Gene expression is the specific combination of genes that are turned on or off (expressed or repressed), and this is what dictates how a cell functions. Gene expression occurs because of certain signals in your body, both inside and outside of your cells.