Differential regulation of target genes by different alleles of the segmentation gene hunchback in Drosophila.

摘要: hunchback (hb) is a key regulatory gene in the early segmentation hierarchy of Drosophila. It codes for transcription factor Cys2-His2 zinc finger type and shows two separate domains its coding region. hb forms morphogenetic gradient middle embryo that required setting spatial boundaries several target genes. We have analyzed molecular lesions found different alleles studied differential effects these on number such find mutants which HB protein lacks functional second domain, regulation genes Kruppel (Kr) knirps (kni) differentially affected. While this domain correct Kr, it not necessary repression kni. Furthermore, mutations affecting lead to decreased stability. The integration expression pattern was be distorted class between gain function or neomorphic phenotypes. were detail they fall into classes, first one interfering with maternal product, leading delayed segmentation. latter appears linked secondary parasegment 4 (PS4) stripe at blastoderm stage.