Analysis of the human LHX3 neuroendocrine transcription factor gene and mapping to the subtelomeric region of chromosome 9.

The Lhx3 LIM homeodomain transcription factor is critical to pituitary organogenesis and motor neuron development. We determined the genomic structure and chromosomal localization of human LHX3. The gene contains seven coding exons and six introns that span 8.7 kilobases in length. The LHX3 gene codes for two functionally distinct isoforms that differ in their amino termini but share common LIM domains and a homeodomain. The functional domains of the LHX3 proteins are encoded by distinct exons. The alternate amino termini and LIM domains lie within individual exons, and the homeodomain is coded by two exons interrupted by a small intron. Human LHX3 maps to the subtelomeric region of chromosome 9 at band 9q34.3, within a region noted for chromosomal translocation and insertion events. Characterization of the genomic organization and chromosomal localization of LHX3 will enable molecular evaluation and genetic diagnoses of pituitary diseases and central nervous system developmental disorders in humans.