An important step to control the amount of RNA or protein in particular types of cells is at the level of transcription of genes. Our lab studies a multifunctional vertebrate transcriptional activator protein known as SBF/Staf/ZNF143. This protein binds to SPH sites within promoters of many genes that produce small stable RNAs (e.g., snRNAs and others) PLUS probably over 2000 promoters of genes that produce mRNAs. Two separate activation domains in this protein direct its action at small RNA vs. mRNA gene promoters. We are using zebrafish as a vertebrate model organism to study the roles of SBF/Staf during development. In vivo studies are coupled with biochemical and molecular biology methods to decipher the mechanisms by which this protein stimulates transcription of various types of genes.