bk1 << N << dnc << bk2
The proximal deletion breakpoint breaks within the dnc transcription unit removing the transcription start sites 1 and 2.
Breakpoint(s) molecularly mapped
-43.9 to -31.2 kb The zero coordinate used in locating the molecular lesions in the Notch deficiencies is the first Eco R1 site in Canton-S DNA proximal to the 3C7 breakpoint of In(1)N76b8 (Kidd et al., 1983); it is 1.1 kb to the right of the zero coordinate used by Artavanis-Tsakonas et al., 1983
Mutant flies have margin defects at the distal wing tip, moderate thickening of wing vein 5 and deltas at the ends of the wing veins.
Heterozygotes show distal notching of the wing and thickening of the wing veins.
The cuticle secreted by zygotic N mutants is crinkled. In the complete absence of zygotic or maternal N the cuticle is very disorganized and thin and often has a hole in the middle. The cells at the leading edge of the closing dorsal epidermis are elongated compared to the wild type, appearing stretched, as do more ventral cells. The midline which eventually forms does not fall along a straight line. For embryos derived from mutant germline clones the defects are more pronounced and dorsal closure fails. The epidermis consists of isolated patches. Df(1)N-81k1 suppresses the dorsal hole phenotypes caused by hep1 and Df(2L)flp147E. Does not suppress dorsal-hole phenotype of pnr or zip mutants.
The RP2 motoneuron duplicated at the expense of the RP2sib. The aCC motoneuron is duplicated at the expense of the pCC interneuron. The Usib fates are duplicated at the expense of the U neurons. The dMP2 is duplicated at the expense of the vMP2. No change was observable in EL cell fate. This phenotype is the reciprocal of that shown for numb mutants. Mutant embryos show excess neuroblast formation characteristic of neurogenic mutants.
Heterozygotes have a marked increase in the number of bristles on the notum.
Dominantly enhances the phenotype of flies carrying Brdmut123+GYmut in a wild-type background.
Hemizygotes exhibit severe defects in the optic lobe and Bolwig's organ. Bolwig's organ has an increased number of cells that form an irregular cluster within the surrounding hyperplastic brain. The number of cells within the optic lobe also seem slightly increased. The morphology of the optic lobe cells has changed, cells are rounded and arranged in a solid cluster.
Homozygotes die as embryos. Heterozygotes show notching of the wing.