Insertion in the 5'UTR of Slbp. In the mutant allele, transcription is initiated in the region downstream of the w gene carried in the inserted P{EP-Δ10} element. This downstream region is derived from sequence that is located 3' to the endogenous w locus. In addition, introns are spliced out of this region in the mutant transcript.
The P{EP} element has an internal deletion from bps 2029-6266.
Females are sterile, but lay normal numbers of morphologically normal eggs.
About half of Slbp10/Slbp12 or Slbp10/Slbp15 animals survive to adulthood. About a third of Slbp10/Slbp19 animals survive to adulthood. Hemizygous mothers lay a normal number of eggs, but none of these eggs complete embryogenesis. These embryos have obvious disruptions of the nuclear cleavage cycles and accumulated nuclei that have aberrant morphologies. The earliest cycles appear somewhat normal. The nuclear cycle defects appear to result from improper chromosome condensation during mitosis. Eggs from mutant mothers never form normal metaphase spindles. Microtubules assemble around improperly condensed DNA, causing the formation of spindles with dramatically altered morphologies. Spindle pole fusion is also frequently observed. Dramatic anaphase bridges are also detected in some embryos, though DNA synthesis is not blocked.
Slbp10, snRNA:U714 has lethal phenotype
Double homozygotes of snRNA:U714 and Slbp10 do not eclose as adults (both single homozygotes develop into adults).
An allelic series can be defined for Slbp alleles with respect to viability: Slbp10 > Slbp19 > Slbp15 >= Slbp12 = Df(3R)3450.