Human TIP49b/RUVBL2 gene: genomic structure, expression pattern, physical link to the human CGB/LHB gene cluster on chromosome 19q13.3

Bacterial DNA helicase RuvB protein is an essential component in homologous recombination and DNA double-strand break repair. Here, we report the gene structure of TIP49b/RUVBL2, a second putative human homologue of the bacte rial RuvB gene. This gene contains 15 exons and 14 introns. The TIP49b/RUVB L2 open reading frame encodes a protein of 463 amino acids, showing 43 % id entity with the RUVBL1 protein. The TIP49b/RUVBL2 gene is physically linked to the human CGB/LHB gene cluster on chromosome 19q13.3. Genomic sequence analysis revealed that the TIP49b/RUVBL2 gene is very close (55 nucleotides in length) to the LHB gene, in the opposite orientation. The very close co -location of the mouse homologues of the human TIP49b/RUVBL2 and LHB genes was also conserved on mouse chromosome 7. Go-ordinated transcriptional regu lation between the TIP49b/RUVBL2 and LHB genes was not observed. TIP49b/RUV BL2, like RUVBL1, was expressed ubiquitously in all human tissues examined and more strongly in testis. As TIP49b/RUVBL2 is expected to be involved in recombination repair and is located in a chromosome region frequently ampl ified in breast cancer, we quantified TIP49b/RUVBL2 gene expression by usin g real-time quantitative RT-PCR in a series of breast tumour samples. None of the tumour samples showed an altered TIP49b/RUVBL2 transcription level r elative to normal breast tissue. (C) 2000 Editions scientifiques et medical es Elsevier SAS.