T. Gutjahr et al., MULTIPLE REGULATORY ELEMENTS DIRECT THE COMPLEX EXPRESSION PATTERN OFTHE DROSOPHILA SEGMENTATION GENE PAIRED, Mechanisms of development, 48(2), 1994, pp. 119-128
The paired (prd) gene of Drosophila belongs to the pair-rule class of
segmentation genes involved in establishing the metameric organization
of the Drosophila body plan. The complex expression pattern of prd ha
s previously been shown to depend upon a number of segmentation genes,
including gap and pair-rule genes. In an attempt to characterize and
analyze the regulatory regions necessary and sufficient for prd expres
sion, we have identified an 18-kb genomic fragment, consisting of the
transcribed portion of prd and 10 kb of 5'- and 5 kb of 3'-flanking re
gion, that is able to rescue prd mutant embryos to full viability. Ana
lysis of a series of prd-lacZ fusion constructs containing progressive
ly reduced lengths of prd 5'-flanking sequences delimits different cis
-regulatory regions. The entire 5'-flanking region directs fusion gene
expression in a pattern similar, but not identical, to the endogenous
prd protein pattern. This 10-kb fragment contains both activator and
repressor regions that mediate the establishment of the seven-stripe p
rd pattern, as well as the splitting into anterior and posterior strip
es for the 14-stripe expression phase. The prd intron in combination w
ith a minimal upstream region (0.15 kb) is able to direct low levels o
f prd-lacZ fusion gene expression in stripes. Information for expressi
on of the anterior dorsal spot and of the early seven-stripe pattern i
s located downstream of the prd coding region. We propose that regulat
ion of prd by pair-rule and gap gene products is mediated by upstream
and downstream cis-regulatory elements. Regulation during separate but
overlapping phases of expression by separable regulatory regions migh
t be a general characteristic of segmentation genes.