Filler in textured paint works like spackling compound to fill the cracks, and dark, flat paint absorbs light to help conceal remaining blemishes. Be aware that dark colors will make your ceiling appear lower, so consider using very dark colors only in normally proportioned or narrow rooms.
In genetics, a promoter is a region of DNA that initiates transcription of a particular gene.
In molecular genetics, a repressor is a DNA- or RNA-binding protein that inhibits the expression of one or more genes by binding to the operator or associated silencers. A DNA-binding repressor blocks the attachment of RNA polymerase to the promoter, thus preventing transcription of the genes into messenger RNA. An RNA-binding repressor binds to the mRNA and prevents translation of the mRNA into protein. This blocking of expression is called repression.