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Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To generate cell- and tissue-specific expression patterns of the reporter gene lacZ in Drosophila, we have generated and characterized 1,426 independent insertion strains using four different P-element constructs. These four transposons carry a lacZ gene driven either by the weak promoter of the P-element transposase gene or by partial promoters from the even-skipped, fushi-tarazu, or engrailed genes. The tissue-specific patterns of beta-galactosidase expression that we are able to generate depend on the promoter utilized. We describe in detail 13 strains that can be used to follow specific cell lineages and demonstrate their utility in analyzing the phenotypes of developmental mutants. Insertion strains generated with P-elements that carry various sequences upstream of the lacZ gene exhibit an increased variety of expression patterns that can be used to study Drosophila development.
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PMID:Generating lineage-specific markers to study Drosophila development. 165 Nov 83

Use of primary culture cells has been limited by the inability to purify most types of cells, particularly cells from early developmental stages. In whole animal cell sorting (WACS), live cells derived from animals harboring a lacZ transgene are purified according to their level of beta-galactosidase expression with a fluorogenic beta-galactosidase substrate and fluorescence-activated cell sorting. With WACS, incipient posterior compartment cells that express the engrailed gene were purified from early Drosophila embryos. Neuronal precursor cells were also purified, and they differentiated into neurons with high efficiency in culture. Because there are many lacZ strains, it may be possible to purify most types of Drosophila cells. The same approach is also applicable to other organisms for which germ-line transformation is possible.
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PMID:Whole animal cell sorting of Drosophila embryos. 189 82

Segmentation in Drosophila melanogaster is controlled by a network of interacting genes, many of which encode a homeodomain that confers sequence-specific binding to DNA. One of these, fushi tarazu (ftz), is a transcription factor that regulates a number of segmentation and homeotic genes, including Antennapedia (Antp). To determine the DNA binding specificity of the ftz homeodomain, we performed DNase I footprint analysis on ftz protein binding sites located near the two Antp promoters using a beta-galactosidase/ftz fusion protein synthesized in E. coli. A consensus sequence for the fusion protein's preferred binding site was derived from 19 sites. The consensus sequence contains an ATTA motif, as do the reported consensus sequences for the engrailed (en), even-skipped (eve), and bicoid (bcd) Drosophila homeodomain proteins. We propose DNA bending as an explanation for the presence of a shared motif between proteins with divergent recognition helices: according to this model, bases in ATTA would not directly contact amino acid side chains of the recognition helix but rather would be necessary for bending of the DNA around the homeodomain, perhaps facilitating important protein-DNA contacts.
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PMID:The DNA binding specificity of the Drosophila fushi tarazu protein: a possible role for DNA bending in homeodomain recognition. 198 71

A Drosophila strain was isolated that carries a lacZ-bearing recombinant P element integrated in the cubitus interruptus Dominant (ci-D) locus. This strain expresses beta-galactosidase in the anterior compartments of embryos and imaginal discs, suggesting that expression of ci-D is anterior-compartment specific. DNA from ci-D was cloned. In situ hybridization to imaginal discs confirmed that ci-D RNA is present only in anterior compartments. ci-D RNA is also limited to the anterior compartments at the germ-band extension stage of embryonic development, although not at earlier stages. In engrailed mutants, ci-D expression was derepressed in the posterior compartments of both embryos and imaginal discs. We postulate that engrailed, which is expressed in only the posterior compartments of embryos and imaginal discs, represses ci-D in these cells.
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PMID:Repression of ci-D in posterior compartments of Drosophila by engrailed. 238 12

The engrailed gene has been identified in Drosophila as an important developmental gene involved in the control of segmentation. Here we describe the embryonic expression of a chicken gene, ChickEn (Darnell et al.: J Cell Biol 103(5):311a, 1986), which contains homology to the Drosophila engrailed gene. Northern blots of early chick embryo tissue poly(A)+ RNA resulted in hybridization to at least three bands expressed predominantly in the brain/head region when probed with ChickEn genomic fragments. Eight cDNA clones generated from embryonic day 6 (stage 29-30) chick brain poly(A)+ RNA are identical in their nucleotide sequence with the ChickEn genomic clone. In situ hybridization to sections of 4-day (stage 24) embryos indicated that ChickEn transcripts were concentrated in the posterior mesencephalon and anterior metencephalon. In cultures of chick cranial neural crest cells (eight to nine somites; stage 9) ChickEn transcripts were localized in a subset (approx. 8%) of cells examined after 2 days in culture. A mouse monoclonal antibody, inv-4D9D4, made by Coleman and Kornberg recognizes the engrailed-like homeo domain of the engrailed and invected proteins (Martin-Blanco, Coleman, and Kornberg, personal communication). Patel, Coleman, Kornberg and Goodman (unpublished) have shown that this antibody binds to the hindbrain of 2-day-old chick embryos. We have confirmed these results and shown that this antibody binds to the same region of 4-day (stage 24) chick brains that in situ hybridization showed contained ChickEn transcripts. This antibody also recognizes a homeo domain-containing ChickEn peptide expressed as a beta-galactosidase fusion protein in Drosophila cell culture. We have not detected ChickEn protein in any tissue prior to eight to nine somites (stage 9). These results delineate the major expression pattern of the ChickEn gene during early (prior to stage 30) embryonic development in the chick.
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PMID:Expression of an engrailed-like gene during development of the early embryonic chick nervous system. 246 80

The homeotic gene Ultrabithorax (Ubx) is expressed in specific parts of Drosophila embryos: in a single metamer in the visceral mesoderm and forming a complex pattern limited to a broad domain in the ectoderm and in the somatic mesoderm. Here we use a linked beta-galactosidase gene to identify cis-acting regulatory sequences. In the visceral mesoderm, correct expression of Ubx depends on localized upstream sequences. In the ectoderm, all galactosidase-positive transformants show the same characteristic pattern. The repeated elements of this basal pattern appear to be a sub-pattern of engrailed (en) expression; they depend on en function as well as on sequences in the Ubx RNA leader. We use a mutant (Haltere-mimic) to show that sequences that normally restrict segmental expression of Ubx in the ectoderm are located downstream from the RNA leader.
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PMID:Differential regulation of Ultrabithorax in two germ layers of Drosophila. 289 41

Because the transcription of the SpHE gene is regulated cell-autonomously and asymmetrically along the maternally determined animal-vegetal axis of the very early sea urchin embryo, its regulators provide an excellent entry point for investigating the mechanism(s) that establishes this initial polarity. Previous studies support a model in which spatial regulation of SpHE transcription relies on multiple nonvegetal positive transcription factor activities (Wei, Z., Angerer, L. M. and Angerer, R. C. (1997) Dev. Biol. 187, 71-78) and a yeast one-hybrid screen has identified one, SpEts4, which binds with high specificity to a cis element in the SpHE regulatory region and confers positive activation of SpHE promoter transgenes (Wei, Z., Angerer, R. C. and Angerer, L. M. (1999) Mol. Cell. Biol. 19, 1271-1278). Here we demonstrate that SpEts4 can bind to the regulatory region of the endogenous SpHE gene because a dominant repressor, created by fusing SpEts4 DNA binding and Drosophila engrailed repression domains, suppresses its transcription. The pattern of expression of the SpEts4 gene is consistent with a role in regulating SpHE transcription in the nonvegetal region of the embryo during late cleavage/early blastula stages. Although maternal transcripts are uniformly distributed in the egg and early cleaving embryo, they rapidly turn over and are replaced by zygotic transcripts that accumulate in a pattern congruent with SpHE transcription. In addition, in vivo functional tests show that the SpEts4 cis element confers nonvegetal transcription of a beta-galactosidase reporter gene containing the SpHE basal promoter, and provide strong evidence that the activity of this transcription factor is an integral component of the nonvegetal transcriptional regulatory apparatus, which is proximal to, or part of, the mechanism that establishes the animal-vegetal axis of the sea urchin embryo.
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PMID:Spatially regulated SpEts4 transcription factor activity along the sea urchin embryo animal-vegetal axis. 1007 34