BLM Mutation Map. A diagram of the of the deletion and missense alleles of BLM used in this study. The amino acids removed by each deletion are: ΔN1 (2-128), ΔN2 (135-235), ΔN3 (241-469), ΔN4 (402-600), ΔH1 (903-1115), ΔC1 (1118-1164) and ΔC2 (1166-1331). The location of the missense allele K695T is shown. The red boxes indicate positions of regions of the N-terminus of BLM that have a high density of aspartic and glutamatic acid residues: region 1 (261-310 = 42% DE) and region 2 (541-570 = 50% DE). Deletion N3 removes a serine-rich region (310-320 = 64%S). The blue box indicates the location of the nuclear localization signal  (NLS = 1331-1350). The two regions of reported in vitro interaction of BLM with TopIIIα (143-213 & 1266-1417) are marked . The helicase domain consists of residues 672-985 and the HRD (Helicase and RNaseD identity domain)  is indicated (1212-1293).
Yankiwski et al. BMC Cell Biology 2001 2:11 doi:10.1186/1471-2121-2-11