Chromosome mapping and expression of human tip49 family genes

TBP-interacting protein 49 (TIP49) was originally identified as a TBP-binding protein, and two related proteins are encoded by individual genes, tip49a 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 interact with various kinds of nuclear factors and have DNA helicase activities. At least, TIP49a has been suggested to act as an autoantigen in some patients with autoimmune diseases. In this study, we investigated the chromosome positions of this family of genes. Human tip49a and tip49b genes were mapped on 3q21 and 19q13.2, respectively. Consistent with the notion that tip49 family genes are essential for cell growth, Northern blot analysis demonstrated that both genes are expressed ubiquitously in human tissues. It is worthy of notice that the testes contained large amounts of the both transcripts. These results are consistent with our previous results from tissue distribution analysis for of TIP49 proteins.