The human tpr gene encodes a protein of 2094 amino acids that has extensive coiled-coil regions and an acidic C-terminal domain.

We recently provided evidence that the human tpr gene encodes a 726 amino acid protein (designated tpr-S) and identified an alternatively spliced transcript that encodes a larger tpr protein with an extended C-terminal domain. In this study, through isolation and sequencing of tpr cDNA clones, we have established that this alternatively spliced transcript encodes a protein of 2094 amino acids (designated tpr-L). The larger tpr protein is predicted to have extensive regions of alpha-helix and several stretches of a heptad repeat that is characteristic of proteins adopting a coiled-coil conformation. Furthermore the carboxy domain of this protein is very rich in acidic residues and exhibits homology (58-80%) to the acidic regions of several nuclear proteins, including the Drosophila engrailed protein, Escherichia coli RNA polymerase sigma subunit and nucleolin. To gain additional insight into the function of tpr we examined the expression of tpr transcripts in tissues from adult rat. The highest levels of tpr transcripts were observed in testis, lung, thymus and spleen.