Neuroblast pattern formation: regulatory DNA that confers the vnd/NK-2 homeobox gene pattern on a reporter gene in transgenic lines of Drosophila.
DNA fragments -0.57, -2.2, -2.9, -5.3, and -8.4 kb in length from the upstream regulatory region of the vnd/NK-2 gene were cloned in the 5'-flanking region of a beta-galactosidase (beta-gal) reporter gene in the P-element pCaSpeR-AUG-beta-gal, and the effects of the DNA on the pattern and time of expression of beta-gal were determined in transgenic embryos. Embryos from 11 lines transformed with -8.4 kb of vnd/NK-2 regulatory DNA expressed beta-gal patterns that closely resemble those of vnd/NK-2. In embryos from four lines transformed with -5.3 kb of vnd/NK-2 DNA, beta-gal was found in the normal vnd/NK-2 pattern in the nerve cord but not in part of the cephalic region. beta-Gal patterns in embryos from transgenic lines containing -0.57, -2.2, or -2.9 kb of vnd/NK-2 DNA did not resemble vnd/NK-2. Null vnd/NK-2 mutant embryos containing the homozygous P-element p[-8.4 to +0.34 beta-gal] expressed little beta-gal in contrast to siblings with a wild-type vnd/NK-2 gene. We conclude that (i) the 8.4-kb DNA fragment from the vnd/NK-2 gene contains the nucleotide sequences required to generate the normal pattern of vnd/NK-2 gene expression, sequences that may be involved in the switch between neuroblast vs. epidermoblast pathways of development, (ii) the 5'-flanking region of the vnd/NK-2 gene between -5.3 and -8. 4 kb is required for vnd/NK-2 gene expression in the most dorsoanterior part of the cephalic region, and (iii) vnd/NK-2 protein is required, directly or indirectly, for maintenance of vnd/NK-2 gene expression.
Saunders
H H
HH
Laboratory of Biochemical Genetics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Koizumi
K
K
Odenwald
W
W
Nirenberg
M
M
D000818:Animals; D030801:Animals, Genetically Modified; D001921:Brain / Q000196:embryology* / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D004247:DNA / Q000502:physiology*; D004330:Drosophila; D029721:Drosophila Proteins; D018507:Gene Expression Regulation, Developmental; D005801:Genes, Homeobox; D017930:Genes, Reporter; D018398:Homeodomain Proteins / Q000235:genetics*; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D014157:Transcription Factors
D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D014157:Transcription Factors; C094797:vnd protein, Drosophila; D004247:DNA