Catalyzes the reduction of the C14-unsaturated bond of lanosterol, as part of the metabolic pathway leading to cholesterol biosynthesis (By similarity). Anchors the lamina and the heterochromatin to the inner nuclear membrane (By similarity). 5alpha-cholest-8,14-dien-3beta-ol + H(+) + NADPH = 5alpha-cholest-8-en-3beta-ol + NADP(+) 4,4-dimethyl-5alpha-cholesta-8,24-dien-3beta-ol + NADP(+) = 4,4-dimethyl-5alpha-cholesta-8,14,24-trien-3beta-ol + H(+) + NADPH 4,4-dimethyl-8,14-cholestadien-3beta-ol + H(+) + NADPH = 4,4-dimethyl-5alpha-cholest-8-en-3beta-ol + NADP(+) Steroid biosynthesis; cholesterol biosynthesis. Interacts with DNA (By similarity). Interaction with DNA is sequence independent with higher affinity for supercoiled and relaxed circular DNA than linear DNA (By similarity). Nucleus; nuclear rim. The Tudor domain may not recognize methylation marks, but rather bind unassembled free histone H3. Belongs to the ERG4/ERG24 family.