Expression analysis and protein localization of the human HPC-1/syntaxin 1A, a gene deleted in Williams syndrome

The HPC-1/syntaxin 1A (STX1A) gene maps to the Williams syndrome (WS) commo nly deleted region on chromosome 7q11.23 and encodes a protein implicated i n the docking of synaptic vesicles with the presynaptic plasma membrane. To assess the potential role of STX1A in the WS phenotype, we carried out exp ression studies at the RNA and protein levels, in fetal and adult human tis sues, RNA in situ hybridization on human embryo sections showed strong STX1 A expression in spinal cord and ganglia, However, in adulthood, this gene w as preferentially expressed in brain, as shown by Northern blot and RT-PCR experiments. Marked expression levels were observed in cerebellum and cereb ral cortex. The STX1A protein was prevalently distributed in the molecular layer of the cerebellar cortex. A qualitative and quantitative analysis usi ng a specific anti-STX1A antibody did not disclose any significant differen ce among frontal, temporal, and occipital poles of the human adult cortex i n the two hemispheres. This is the first study focused on STX1A expression in humans. Our results indicate that this gene is strongly expressed in cer ebral areas involved in cognitive process, supporting a likely role in the neurological symptoms of WS. (C) 1999 Academic Press.