X-ray irradiation generates a >4kb deletion in jumu that removes the first exon.
jumuX3 embryos are defective in head involution, displaying an anterior open phenotype. Some jumuX3 mutants show a defect in dorsal closure and in germ band retraction. In jumuX3 embryos, the dorsal epidermal cells only partially elongate. These embryos exhibit loss of a large number of both CNS and PNS neurons. Occasionally, all or most of the CNS neurons in a hemisegment are lost.