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R A Schulz

Publications and source records attributed to R A Schulz.

At least 37 records · Page 2Linked to original sources
PubMed1996

Expression of the D-MEF2 transcription in the Drosophila brain suggests a role in neuronal cell differentiation.

D-MEF2 is a MADS domain transcription factor expressed in the cardiac, somatic, and visceral muscle cell lineages in the Drosophila embryo. Genetic studies have demonstrated that D-mef2 gene function is required for the proper differentiation of all three of these muscle types. We show that D-MEF2 is also expressed in a limited number of other cells types during development, including Kenyon cells present in the mushroom bodies of the Drosophila brain. This finding suggests a role for D-mef2 in neuron differentiation. To investigate D-mef2 expression in muscle and Kenyon cells, we assayed 26 kb of D-mef2 5'-flanking and intragenic DNA for regulatory sequences controlling the expression of the gene. Our results show that separable enhancer sequences direct D-mef2 gene expression in the myogenic and neuronal cell lineages. The identification of these regulatory DNAs provides a starting point for the analysis of transcriptional regulators controlling the cell-specific expression of D-mef2 and a means to address the function of D-mef2 in Kenyon cell differentiation.

Animals↗
PubMed1995

Requirement of the ETS domain transcription factor D-ELG for egg chamber patterning and development during Drosophila oogenesis.

The D-elg gene encodes an ETS domain transcription factor that functions in Drosophila oogenesis. D-elg belongs to a small group of genes that are required for the formation of both the anteroposterior and dorsoventral axes of the egg chamber. During oogenesis in D-elg mutant females, the spatial localization of oskar and gurken mRNAs in the oocyte is disrupted and a follicle cell enhancer trap marker identifies dorsoventral polarity defects. Also, specialized follicle cells, called border cells, fail to migrate from their anterior location to a position adjacent to the developing oocyte. Consistent with these phenotypes, D-elg shows genetic interactions with two genes required for normal egg chamber differentiation.

Animals↗
PubMed1995

Requirement of MADS domain transcription factor D-MEF2 for muscle formation in Drosophila.

Members of the myocyte enhancer binding factor-2 (MEF2) family of MADS (MCM1, agamous, deficiens, and serum response factor) box transcription factors are expressed in the skeletal, cardiac, and smooth muscle lineages of vertebrate and Drosophila embryos. These factors bind an adenine-thymidine-rich DNA sequence associated with muscle-specific genes. The function of MEF2 was determined by generating a loss-of-function of the single mef2 gene in Drosophila (D-mef2). In loss-of-function embryos, somatic, cardiac, and visceral muscle cells did not differentiate, but myoblasts were normally specified and positioned. These results demonstrate that different muscle cell types share a common myogenic differentiation program controlled by MEF2.

Animals↗
PubMed1995

A series of mutations in the D-MEF2 transcription factor reveal multiple functions in larval and adult myogenesis in Drosophila.

The D-mef2 gene encodes a MADS domain transcription factor expressed in differentiated muscles and their precursors in the Drosophila embryo. Embryos deficient for D-MEF2 protein due to a deletion of upstream transcriptional control sequences fail to form muscle, suggesting that the gene is required for muscle cell differentiation. To directly demonstrate a role for D-mef2 in embryonic myogenesis, we isolated gene mutants containing EMS-induced point mutations, characterized the effects of these mutations on D-MEF2 protein stability and nuclear localization, and analyzed the resulting muscle phenotypes. Our results show that in the somatic muscle lineage, D-mef2 is required for both the formation and patterning of body wall muscle. In the absence of somatic myogenesis, there is extensive apoptosis among the myoblast cell population. In contrast, in the cardiac muscle lineage, morphogenesis of the dorsal vessel occurs normally but the three myosin subunit genes are not expressed. Mutant embryos also exhibit an abnormal midgut morphology, which correlates with the absence of alpha PS2 integrin gene expression and muscle-specific enhancer function, suggesting that D-mef2 regulates the inflated locus which encodes this integrin subunit. D-MEF2 is also expressed in adepithelial cells and rare D-mef2 transheterozygous mutant adults fail to fly, consistent with defects observed in the indirect flight muscles. These results demonstrate that the D-mef2 gene has multiple functions in myogenesis and tissue morphogenesis during Drosophila development.

Animals↗
PubMed1994

D-MEF2: a MADS box transcription factor expressed in differentiating mesoderm and muscle cell lineages during Drosophila embryogenesis.

The myocyte enhancer factor (MEF) 2 family of transcription factors has been implicated in the regulation of muscle transcription in vertebrates. We have cloned a protein from Drosophila, termed D-MEF2, that shares extensive amino acid homology with the MADS (MCM1, Agamous, Deficiens, and serum-response factor) domains of the vertebrate MEF2 proteins. D-mef2 gene expression is first detected during Drosophila embryogenesis within mesodermal precursor cells prior to specification of the somatic and visceral muscle lineages. Expression of D-mef2 is dependent on the mesodermal determinants twist and snail but independent of the homeobox-containing gene tinman, which is required for visceral muscle and heart development. D-mef2 expression precedes that of the MyoD homologue, nautilus, and, in contrast to nautilus, D-mef2 appears to be expressed in all somatic and visceral muscle cell precursors. Its temporal and spatial expression patterns suggest that D-mef2 may play an important role in commitment of mesoderm to myogenic lineages.

Amino Acid Sequence↗
PubMed1993

Ets oncogene-related gene Elg functions in Drosophila oogenesis.

Members of the ets gene family encode transcription factors that regulate the expression of a variety of cellular and viral genes including several protooncogenes. We have utilized Drosophila to elucidate the in vivo function of one family member. We show by complementation rescue and sequence analysis that the female sterile mutant tiny eggs (tne) is an allele of the Drosophila Ets-related gene Elg (also called D-elg). The mutation of a highly conserved tyrosine residue in the ETS DNA-binding domain of the Elg gene product demonstrates that normal gene function is required for proper follicle cell migration, chorion formation, and nurse cell-chromosome decondensation during Drosophila oogenesis.

Amino Acid Sequence↗
PubMed1993

Characterization of lethal alleles of D-elg, an ets proto-oncogene related gene with multiple functions in Drosophila development.

We have used genetic complementation rescue to identify two lethal alleles of D-elg, an ets proto-oncogene related gene of Drosophila. Animals that are hemizygous or trans-heterozygous for the alleles die as pharate adults, demonstrating normal gene function is required to complete Drosophila development. Females trans-heterozygous for the 1(3)902 lethal allele and the previously characterized tne female sterile allele produce embryos with abdominal segmentation defects. This finding implicates a role for the D-elg gene in anterior-posterior patterning. The cloning and sequencing of the lethal alleles identified molecular mutations that may result in ELG protein truncation, altered ELG protein interactions, or defective D-elg mRNA splicing.

Alleles↗
PubMed1992

Drop out: a third chromosome maternal-effect locus required for formation of the Drosophila cellular blastoderm.

drop out (dop) is a recessive maternal-effect locus identified in a screen for female-sterile mutations in Drosophila polytene region 71C-F. Phenotypic analyses of the dop mutation indicate that the gene is required for proper formation of the cellular blastoderm. In embryos derived from either homozygous or hemizygous dop mothers, cytoplasmic clearing, nuclear migration and division, and pole cell formation appear normal. However, developmental defects are observed prior to and during cellularization of the blastoderm. At the beginning of nuclear cycle 14, the distinct separation of the internal yolk mass and the cortical cytoplasm breaks down. Subsequently, a population of somatic nuclei located at the periphery of the syncytial blastoderm becomes irregularly spaced and nonuniform in their distribution. Despite a somewhat regular formation of the cortical actin network, cellularization in mutant embryos is extremely variable. Such embryos fail to gastrulate normally and produce variable amounts of defective cuticle. Overall, our analyses suggest that the dop gene functions in maintaining the separation of yolk and cortical cytoplasm and in stabilizing the distribution of somatic nuclei in the Drosophila syncytial blastoderm.

Animals↗
PubMed1992

Molecular characterization and structural organization of D-elg, an ets proto-oncogene-related gene of Drosophila.

We have continued the molecular analysis of D-elg, a member of the Drosophila ets gene family. Based on the characterization of cDNA and genomic sequences, the D-elg gene contains five exons and four introns and produces a mRNA with an open reading frame of 464 amino acids. Consistent with this analysis, in vitro translation of a near full-length D-elg cRNA yields a protein with a molecular weight of approximately 56 kDa. D-elg shows significant homology to other ets proteins in the amino-terminal A domain and strong homology in the carboxy-terminal ETS domain. The D-elg protein is most similar to the alpha-subunit of the mouse GA-binding protein.

Amino Acid Sequence↗
PubMed1991

Endoderm-specific expression of the Drosophila mex1 gene.

The Drosophila mex1 gene is one of several genes clustered within a 10-kb interval of polytene region 71CD that includes the ecdysone-regulated Eip28/29 gene. mex1 is expressed in several developmental stages, with gene transcripts accumulating initially in 9- to 12-hr embryos. During embryogenesis, mex1 exhibits an endoderm-specific pattern of expression. mex1 transcripts are first detected in the anterior and posterior midgut primordia of stage 12 embryos; subsequently, mex1 mRNA accumulates solely in the differentiating embryonic midgut. DNA sequence analysis reveals that the mex1 gene encodes an unusual cysteine-rich polypeptide.

Amino Acid Sequence↗
PubMed1991

D-elg, a member of the Drosophila ets gene family: sequence, expression and evolutionary comparison.

We have cloned a cDNA from the Drosophila elg gene, a new member of the ets family of genes. The D-elg gene is located at 97D on chromosome 3R and is expressed as a 2.0kb RNA in the embryos, pupae and adults, with no detectable expression in third instar larvae. D-elg expression is observed in all cells of early stage embryos, prior to transcriptional activation of the zygotic genome, and is maintained throughout embryogenesis with no regional localization. The cDNA encodes a predicted protein of 15.4kD that has an 86 amino acid sequence with 72% similarity to the carboxy terminal region of the Drosophila ets-2 gene. Comparison with all known ets genes allows us to define a minimal region required for assignment to the ets gene family.

Amino Acid Sequence↗
PubMed1990

The Drosophila melanogaster z600 gene encodes a chromatin-associated protein synthesized in the syncytial blastoderm.

The Drosophila melanogaster z600 gene is zygotically expressed with gene transcripts accumulating transiently during early embryogenesis. Based on nucleotide sequence analysis, z600 is predicted to encode a small, basic, histone-like protein. Antibodies generated against a beta-galactosidase::z600 fusion protein immunoprecipitated the z600 in vitro translation product and detected a z600 protein present predominantly in 2- to 4-h embryos. We localized the z600 protein in whole-amount embryos by indirect immunofluorescence. These studies show that the protein is located in the nucleus and associated with chromatin in the syncytial blastoderm.

Animals↗
PubMed1990

cis-acting sequences required for the germ line expression of the Drosophila gonadal gene.

We have identified two DNA sequences required for the proper germ line expression of the Drosophila gonadal (gdl) gene. A 53-bp region located from -328 to -276 relative to the gdlM transcription start site was required for the expression of a gdl-lacZ gene fusion in the male germ line. This sequence resides within the upstream z600 gene; however, z600 expression was undetectable in male germ cells. A 30-bp region located from -5 to +25 relative to the gdlF transcription start site was required for the expression of gdl-lacZ gene fusion in the female germ line.

Animals↗
PubMed1990

Expression of the Drosophila gonadal gene: alternative promoters control the germ-line expression of monocistronic and bicistronic gene transcripts.

The Drosophila gonadal (gdl) gene is differentially expressed in the male and female germ lines. In males, expression in the gdlM mode results in a 1200-/1500-nucleotide RNA pair, whereas in females, expression in the gdlF mode results in a 1000-/1300-nucleotide RNA pair. Since the two expression modes are a result of alternative promoter usage, the sex-specific transcripts differ at their 5' ends. These sequence differences affect the coding capacity of the gene. A common open reading frame (ORF) of 193 codons (ORF193) is present in all four gdl transcripts; a consequence of the additional sequences at the 5' end of the gdlM transcripts is the presence of an additional ORF of 39 codons (ORF39). Translation of gdlF and gdlM cRNAs in a reticulocyte lysate reveals that these transcripts can serve as monocistronic and bicistronic mRNAs in vitro. An analysis of germ-line transformants harboring gdl-lacZ gene fusions provides information on gdl gene expression during gametogenesis. The fusion genes are transcribed and translated in the germ line; beta-galactosidase activity is detected in premeiotic and postmeiotic spermatogenic stages in males, and in nurse cells and oocytes of developing egg chambers in females. Both gdlM ORFs are used because transformant lines expressing the lacZ gene, fused in frame with either ORF39 or ORF193, are positive for beta-galactosidase activity in the testes. These studies also reveal that separable transcription control elements are responsible for gdl expression in the male and female germ lines.

Animals↗
PubMed1989

Dorsal expression of the Drosophila z600 gene during early embryogenesis.

The Drosophila z600 gene is a member of an overlapping gene cluster located in the 71CD interval of chromosome 3. We have used several approaches to study the spatial and temporal expression of z600 during embryogenesis. Northern analysis shows that z600 is zygotically expressed, with gene transcripts accumulating transiently during early embryo-genesis. The localization of z600 transcripts in embryo sections by in situ hybridization reveals a dynamic pattern of RNA distribution. z600 RNA is distributed throughout the embryo during the midsyncytial blastoderm stage, becomes concentrated dorsally and posteriorly during cellularization, and persists in the dorsal-most region of the embryo during gastrulation and germ band extension. z600 transcript accumulation is altered in dorsalized or ventralized mutant embryos, suggesting that z600 is directly or indirectly regulated by genes specifying the dorsal-ventral pattern in the embryo. An analysis of germ line transformants harboring a z600-lacZ gene fusion demonstrates that a 276-bp DNA region contains the sequences responsible for dorsal activation, but not ventral repression, of z600 gene expression during early embryogenesis.

Animals↗
PubMed1989

Diverse expression of overlapping genes: the Drosophila Eip28/29 gene and its upstream neighbors.

The Eip28/29 gene of Drosophila is known to be regulated by the steroid hormone ecdysone in Kc cells and other cell lines. An investigation of Eip28/29 gene expression in intact animals has led to the discovery of two new genes on its 5' flank. Together these three genes generate at least seven distinct transcripts with diverse patterns of developmental expression. gonadal (gdl) is transcribed on the same strand as Eip28/29 and is expressed in two modes. gdlM transcripts, observed exclusively in the testes, are 1200 and 1500 N long, differing by their polyadenylation site but probably otherwise identical; gdlF transcripts are 900 and 1200 N long and share their terminal exons with the two gdlM transcripts. In adults they are exclusively ovarian, but they are also present in early embryos and, at a lower abundance, in Kc cells. In each mode, the longer transcript results from use of a polyadenylation site within the 5' exon of Eip28/29. The shared region includes 3' noncoding sequences of gdl transcripts and 5' flanking DNA and 5' noncoding sequences of Eip28/29. gdl expression in Kc cells is, however, unaffected by ecdysone. z600 is more distal to Eip28/29 but still contained at least in part within the 2 kb upstream of that gene. Its 600 N transcript is expressed predominantly during the first few hours of embryogenesis. Finally, the Eip28/29 transcripts are present at low levels during most developmental stages.

Animals↗