Chromosome mapping and expression of human tip49 family genes

TBP-interacting protein 49 (TIP49) was originally identified as a TBP-bindi ng protein, and two related proteins are encoded by individual genes, tip49 a and b. Although the function of this gene family has not been elucidated, they are supposed to play a critical role in nuclear events because they i nteract with various kinds of nuclear factors and have DNA helicase activit ies. At least, TIP49a has been suggested to act as an autoantigen in some p atients with autoimmune diseases. In this study, we investigated the chromo some positions of this family of genes. Human tip49a and tip49b genes were mapped on 3q21 and 19q13.2, respectively. Consistent with the notion that t ip49 family genes are essential for cell growth, Northern blot analysis dem onstrated that both genes are expressed ubiquitously in human tissues. It i s worthy of notice that the testes contained large amounts of the both tran scripts. These results are consistent with our previous results from tissue distribution analysis for of TIP49 proteins.