Three hormone receptor-like Drosophila genes encode an identical DNA-binding finger.

Abstract

The putative finger domain of knirps (kni), a member of the gap class of segmentation genes, was used to isolate two sequence‐related genes of Drosophila melanogaster under reduced stringency hybridization conditions. The two kni homologous genes map close to kni in the proximal portion of the third chromosome. One of them is the previously identified gene knirps‐related (knrl), kni and knrl are spatially co‐regulated in both early and late stages of embryogenesis. Their posterior domains of expression at blastoderm stage are under the control of the maternal pattern organizer gene nanos. In contrast, the expression of the second kni homologous gene is restricted to the late embryonic gonads. Due to its site of expression, we termed this gene ‘embryonic gonad’ (egon). In addition to the conserved DNA‐binding domain, these three genes share an additional sequence of 19 amino acids, the kni‐box, adjacent to the finger region. The identical N‐terminal Cys/Cys finger encoded by each of the three genes suggests that they code for DNA‐binding proteins which might bind to similar (or even identical) target sequences.

Evolution of the nuclear receptor superfamily: early diversification from an ancestral orphan receptor

“…These are the KNI group (Drosophila KNI, KNRL and EGON genes; Nauber et al 1988, Oro et al 1988, Rothe et al 1989, the Caenorhabditis ODR-7 gene (Sengupta et al 1994), the human DAX-1 and SHP-1 genes (Zanaria et al 1994, Seol et al 1996, Swain et al 1996 and the Drosophila Trithorax gene (Stassen et al 1995).…”

Identification of ecdysone response elements by analysis of the Drosophila Eip28/29 gene.

“…There is precedent in the literature for competitive interactions between steroid receptors and other proteins for binding to HREs (Briiggemeier et al 1990;Crawford and Chapman 1990). It is intriguing to note that the steroid receptor-like proteins encoded by the Diosophila genes E75 (Segraves and Hogness 1990), CPl (Shea et al 1990), tU (Pignoni et al 1990), svp (Mlodzik et al 1990), kni (Nauber et al 1988), kml (Oro et al 1988), and egon (Rothe et al 1989) all have sequences suggesting binding to TGACCT-related half-sites (for a summary, see Pignoni et al 1990). The CFl product has been shown experimentally to bind to such a sequence (Shea et al 1990).…”

Long-range repression in the Drosophila embryo.

“…For example, the posterior border of eve stripe 3 is established by the gap repressor knirps (kni; ref. 7), which is a member of the nuclear receptor superfamily, and is expressed in the presumptive abdomen in early embryos (8). There are at least five knibinding sites in the stripe 3 enhancer, two of which map within 100 bp of critical d-STAT activator sites within the enhancer (9).…”