Peptide sequence: LPLQREPLYN WQATKASLKE RFAFLFNSEL LSDVRFVLGK GRGAAAAGGP Sequence homology: Cow: 100%; Guinea Pig: 100%; Human: 100%; Mouse: 100%; Rat: 100%. The C-terminus of BTBD1 binds topoisomerase I. The N-terminus contains a proline-rich region and