noun, plural: transactivations
(molecular biology, genetics) The stimulation of transcription by expressing an intermediate (transactivator) protein
Transactivation refers to the increased rate of transcription. It can be stimulated by natural or by artificial means. By natural means, transactivation can be stimulated by endogenous transactivators, e.g. cellular or viral proteins. For instance, Human Immunodeficiency Virus (HIV) can encode transactivators to increase their gene expression. This is also what human T-lymphotropic virus or human T-cell lymphotropic virus (HTLV) does. HTLV is also involved in causing a type of cancer called adult T-cell leukemia or lymphoma. The latter can cause leukemia primarily by interacting and increasing the expression of a cellular proto-oncogene. HTLV is also capable of infecting T cells and inside cause an increased expression of transcription factors and cytokines that in turn stimulate the proliferation of T cells leading o lymphoma.
Transactivation can also be induced artificially. Artificial transactivation of a gene is done by inserting a transactivator gene and promoter segments of DNA into a cell. This results in the expression of a transcription factor that binds to the promoter segment of the DNA resulting in the expression of that gene.