Recessive, temperature-sensitive embryonic lethal mutant . Maintain at 15C, most embryos will hatch. Nearly all embryos fail to hatch at 25C. Centrosomes are detached from nuclear spindle envelope in one-cell stage embryos; sometimes reattach to pronuclei; sometimes stay unattached throughout prophase until nuclear envelope breakdown. Mis-sense mutation in Q367P. Hook family member. Localizes to nuclear envelope and centrosomes; interacts with SUN domain proteins at nuclear envelope and interacts with dynein.