Fine structure of the human translocation protein 1 (HTP1/TLOC1) gene.

We characterized the genomic region corresponding to the human translocation protein 1 (HTP1/TLOC1) cDNA previously reported. An experiment using rapid amplification of cDNA ends revealed that the transcription initiation site was at -12 bp upstream from the translation initiation codon ATG. Using direct-sequencing PCR, we determined precise intron/exon boundaries and intron-exon composition of the gene. The gene region spanned approximately 28 kb and was composed of eight exons and seven introns. The lengths of exons and introns range from 48 to > 1707 bp and from 0.25 to 8.2 kb, respectively. The translation initiation codon and the termination codon were located in exons 1 and 8, respectively. The nucleotide sequences of the introns were also determined in the region around the intron/exon boundaries for 63 to 442 bp. All of the sequences around the intron/exon boundaries were consistent with the 5' and 3' consensus sequences for splice junctions of transcribed genes. Putative lariat sequences were identified between -28 and -64 nucleotides from the 3' splice junction for all seven introns. DNA walking experiments revealed a promoter region of 600 bp. The promoter region did not contain an apparent TATA box or a CAT box but did contain Evi-1, GATA, v-Myb, MZF1, and AP-1 binding sites--factors known as regulatory factors on expression of the gene in blood cells. Therefore, this gene may be one such gene.