The biosynthesis of BC200 RNA occurs at the cell body of a neuron and requires upstream promoter elements, downstream internal promoter elements (intragenic A and B boxes), at least two transcription factor binding sites, a TATA-like sequence, TATA-box binding protein (TBP), and RNA polymerase III.
There is a deletion of sequences between -100 and -1 in the DNA that blocks transcription activity, revealing that the transcription complex must interact with this 100-bp sequence of the upstream region for proper synthesis of BC200 RNA. The TATA-box binding protein (TBP) binds here, and when inhibited, BC200 RNA levels decrease, indicating that the 100 base pair region and TBP are critical players in the biosynthesis of BC200 RNA.
In addition to upstream elements, there is an upstream TATGAAA sequence (similar to TATA box sequence) at positions -28 to -22 which, when deleted, compromises transcription, revealing this TATA-like sequence as another critical player in the synthesis of BC200 RNA. However, transcription is not dependent on the TATA-box binding protein binding to the TATA-like sequence.
Both upstream and internal promoter elements are also essential for BC200 RNA synthesis. There are two types of upstream promoter elements in the 100 base pair region: one proximal to the transcription start site and associated with downstream transcription factor binding sites, and the other between nucleotides -36 and -100 and not associated with downstream binding sites. The internal promoter elements are intragenic A and B boxes with A located at position +5 to +15 and B located at position +78 to +88. Any mutation in these boxes can result in a decrease of BC200 RNA.
Because BC200 RNA acts as a translational regulator, it is then transported to the dendrites to bind to specific proteins involved in translation and inhibit their activity (see next section).