Ho Y T, Weber S M, Lim J K
Department of Biology, University of Wisconsin, Eau Claire 54702-4004.
Genetics. 1993 Jul;134(3):895-908. doi: 10.1093/genetics/134.3.895.
A transposable hobo element in the Notch locus of the Uc-1 X chromosome, which does not interfere with the normal expression of the locus, interacts with other hobo elements in the same X chromosome to produce Notch mutations. Almost all of these mutations are associated with deficiencies, inversions or other rearrangements, and hobo elements are present at each of the breakpoints. The Uc-1 X chromosome produces the Notch mutations at a rate of 4-8% in both sexes of flies in a strain that has been inbred for 96 generations. At least two-thirds of the mutations are produced in clusters suggesting that they have originated in mitotic (premeiotic) germ cells of the Uc-1 inbred strain. The interaction of hobo elements in the Uc-1 X chromosome can be repressed by at least two different mechanisms. One found in three inbred strains not related to the Uc-1 strain involves a maternal effect that is not attributable to the actions or products of hobo elements. Repression by this mechanism is manifested by a clear reciprocal cross effect so that the production of Notch mutations is repressed in the daughters of Uc-1 males, but not in the daughters of Uc-1 females. The other mechanism apparently requires genetic factors and/or hobo elements in a particular strain of Oregon-R; complete repression is present in both types of hybrids between Uc-1 and this strain.
Uc - 1 X染色体的Notch基因座中的一个可转座的hobo元件，它不干扰该基因座的正常表达，与同一X染色体中的其他hobo元件相互作用，产生Notch突变。几乎所有这些突变都与缺失、倒位或其他重排有关，并且在每个断点处都存在hobo元件。在一个已经连续自交96代的品系中，Uc - 1 X染色体在雌雄果蝇中产生Notch突变的频率为4% - 8%。至少三分之二的突变是以簇的形式产生的，这表明它们起源于Uc - 1自交品系的有丝分裂（减数分裂前）生殖细胞。Uc - 1 X染色体中hobo元件的相互作用可以通过至少两种不同的机制被抑制。在与Uc - 1品系无关的三个自交品系中发现的一种机制涉及母性效应，这并非归因于hobo元件的作用或产物。这种机制引起的抑制表现为明显的正反交效应，即Notch突变的产生在Uc - 1雄性的子代中受到抑制，但在Uc - 1雌性的子代中不受抑制。另一种机制显然需要俄勒冈 - R特定品系中的遗传因子和/或hobo元件；在Uc - 1与该品系的两种杂交类型中都存在完全抑制。
