The Alternatively Spliced Form of Human Mitochondrial Transcription Factor a Displays Altered DNA Binding Properties

Abstract

Human mitochondrial transcription factor A (h-mtTFA) is the primary activator of transcription in human mitochondria. Recently, an alternatively spliced form of h-mtTFA has been identified in which the fifth exon, comprising a significant portion of the second HMG-box DNA binding domain, is absent. The presence of this protein in vivo is confirmed, although it is not nearly as abundant as its mRNA level suggests. The DNA binding abilities of this alternatively spliced form of h-mtTFA suggest that it interacts only weakly at the major promoter sequences, thereby accounting for the inability of this form of h-mtTFA to activate transcription.