Human SULT1A3 pharmacogenetics: gene duplication and functional genomic studies

Area of Science:

• Pharmacogenomics
• Human Genetics
• Enzyme kinetics

Background:

• Sulfotransferase (SULT) 1A3 catalyzes catecholamine conjugation, with genetic variations influencing its activity.
• Previous studies identified significant SULT1A3 nonsynonymous single nucleotide polymorphisms (cSNPs).
• The Human Genome Project suggested a potential duplication of the SULT1A3 gene.

Purpose of the Study:

• To investigate the suspected duplication of the SULT1A3 gene.
• To identify and characterize novel polymorphisms in the SULT1A3 gene.
• To determine the functional impact of identified polymorphisms on SULT1A3 enzyme activity.

Main Methods:

• Polymerase chain reaction (PCR)-based assays.
• Fluorescence in situ hybridization (FISH).
• Gene resequencing and functional genomic studies.
• Reverse transcription PCR (RT-PCR).

Main Results:

• Confirmed the presence of two SULT1A3 genes, SULT1A3 and SULT1A4, on chromosome 16 in all studied human DNA samples.
• Identified 11 novel polymorphisms, including three nonsynonymous cSNPs.
• Demonstrated that two cSNPs (C302T and C302A) decreased SULT1A3 enzyme activity and protein levels.
• Confirmed transcriptional activity of both SULT1A3 and SULT1A4 genes.

Conclusions:

• The SULT1A3 gene is duplicated, resulting in SULT1A3 and SULT1A4.
• Novel polymorphisms, particularly C302T and C302A, affect SULT1A3 enzyme function.
• The SULT1A3 gene duplication must be considered in future studies of individual SULT1A3 activity variations.