Transcriptional regulation of the mouse gene encoding the α-4 subunit of the GABAA receptor

The gamma-aminobutyric acid type A receptors (GABA(A)-Rs) mediate fast inhibitory synaptic transmission in the brain. The alpha4 subunit of the GABA(A)-R confers distinct pharmacological properties on the receptor and its expression pattern exhibits plasticity in response to physiological and pharmacological stimuli, including withdrawal from progesterone and alcohol. We have analyzed the promoter region of the mouse GABRA4 gene that encodes the alpha4 subunit and found that the promoter has multiple transcriptional initiation sites and lacks a TATA box. The minimal promoter for GABRA4 spans the region between -444 to -19 bp relative to the coding ATG and shows high activity in cultured mouse cortical neurons. Both Sp3 and Sp4 transcription factors can interact with the two Sp1 binding sites within the minimal promoter and are critical for maximal activity of the promoter in neurons.