Alternative titles; symbols
HGNC Approved Gene Symbol: TLX1NB
Cytogenetic location: 10q24.31 Genomic coordinates (GRCh38): 10:101,089,321-101,141,266 (from NCBI)
By searching for genes upstream of the TLX1 gene (186770) on chromosome 10, Greene et al. (2007) identified the TD1 gene, which is transcribed in the opposite orientation to TLX1. The deduced 122-amino acid TD1 protein has a calculated molecular mass of 13.4 kD. It is proline rich and has 8 potential serine/threonine phosphorylation sites and a C-terminal leucine zipper-like region with a predicted amphipathic alpha-helical structure. TD1 was predicted to be a nuclear protein. Database analysis revealed conservation of the TD1 coding region only in primates, although part of the upstream region is conserved in several other mammalian species. RT-PCR analysis of leukemia cell lines detected TD1 expression predominantly in lines that expressed TLX1.
Greene et al. (2007) determined that the TD1 gene contains 3 exons and spans about 42 kb. The first 2 exons are noncoding. The 5-prime UTR contains 14 upstream initiation codons and 11 upstream ORFs of greater than 10 amino acids in length. The 161-bp intergenic region between TD1 and TLX1 is highly conserved between mouse and human and contains numerous GC boxes and a centrally located CCAAT box embedded within a CpG island. It has no discernible TATA box. Reporter gene assays showed that the intergenic region had robust bidirectional promoter activity for expression of both TD1 and TLX1.
By genomic sequence analysis, Greene et al. (2007) mapped the TD1 gene to chromosome 10q24. It lies upstream of the TLX1 gene in a head-to-head orientation.
Greene, W. K., Sontani, Y., Sharp, M. A., Dunn, D. S., Kees, U. R., Bellgard, M. I. A promoter with bidirectional activity is located between TLX1/HOX11 and a divergently transcribed novel human gene. Gene 391: 223-232, 2007. [PubMed: 17303350] [Full Text: https://doi.org/10.1016/j.gene.2006.12.034]