Alternative 5C actin transcripts are localized in different patterns during Drosophila embryogenesis

Burn, Timothy C.; Vigoreaux, Jim O.; Tobin, Sara L.

doi:10.1016/s0012-1606(89)80008-9

Cited by 44 publications

(37 citation statements)

References 29 publications

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“…In all transgenic lines obtained (Ն20 independent lines for each of the pFAs and pFAas constructs), we never observed silencing of the miniwhite gene under this condition, indicating that the Fab-7 PRE is switched into the activated mode. We verified that transcription through Fab-7 occurred in the expected pattern by RNA in situ hybridizations in embryos and third-instar larval tissues (Burn et al 1989; data not shown). In contrast, after the excision of the actin5c promoter from the transgene, the miniwhite gene was almost completely repressed (Fig.…”

Section: A Transgenic Reporter System To Study the Function Of Noncodsupporting

confidence: 57%

Intergenic transcription through a Polycomb group response element counteracts silencing

Schmitt

Prestel²,

Paro³

2005

Genes Dev.

216

184

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Polycomb group response elements (PREs) mediate the mitotic inheritance of gene expression programs and thus maintain determined cell fates. By default, PREs silence associated genes via the targeting of Polycomb group (PcG) complexes. Upon an activating signal, however, PREs recruit counteracting trithorax group (trxG) proteins, which in turn maintain target genes in a transcriptionally active state. Using a transgenic reporter system, we show that the switch from the silenced to the activated state of a PRE requires noncoding transcription. Continuous transcription through the PRE induced by an actin promoter prevents the establishment of PcG-mediated silencing. The maintenance of epigenetic activation requires transcription through the PRE to proceed at least until embryogenesis is completed. At the homeotic bithorax complex of Drosophila, intergenic PRE transcripts can be detected not only during embryogenesis, but also at late larval stages, suggesting that transcription through endogenous PREs is required continuously as an anti-silencing mechanism to prevent the access of repressive PcG complexes to the chromatin. Furthermore, all other PREs outside the homeotic complex we tested were found to be transcribed in the same tissue as the mRNA of the corresponding target gene, suggesting that anti-silencing by transcription is a fundamental aspect of the cellular memory system. Chromosomal elements termed PREs (Polycomb group response elements) mediate the mitotic inheritance of transcriptional programs, thus ensuring the stable propagation of cell fates throughout development. In the repressed state, PREs act as silencers by recruiting Polycomb group (PcG) complexes to chromatin. When in the activated mode, however, PREs are controlled by the counteracting trithorax group (trxG) proteins, which in turn promote the formation of a transcriptionally competent chromatin structure (for review, see . Besides the well studied homeotic genes in the Drosophila bithorax complex (BX-C), PREs have been shown to be associated with a number of target genes (Kassis 1994;Maurange and Paro 2002;Bloyer et al. 2003;Ringrose et al. 2003). However, despite extensive analyses of the dynamics of PcG and trxG protein association with a PRE and requirements during the establishment of either the silenced or the activated state (Orlando et al. 1998;Poux et al. 2001;Mohd-Sarip et al. 2002;Déjardin and Cavalli 2004), it is not known how the decision between the recruitment of either repressive PcG or activating trxG complexes to a PRE is taken.There is accumulating evidence that silencing represents the default state of these elements, whereas the conversion of a PRE into the active chromatin mode is triggered by the embryonic activation of the target gene promoter (Busturia and Bienz 1993;Chan et al. 1994;Paro 1998, 1999;Klymenko and Müller 2004;Sengupta et al. 2004). However, it is not clear how this transcriptional activity is communicated to a PRE and, as a consequence, which mechanism regulates the epigenetic switch of a PRE into t...

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Section: A Transgenic Reporter System To Study the Function Of Noncodsupporting

confidence: 57%

Intergenic transcription through a Polycomb group response element counteracts silencing

Schmitt

Prestel²,

Paro³

2005

Genes Dev.

216

184

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“…Since the coding region lies entirely in exon 3, the actin product is the same in both cases. But the presence of two promoters provides the organism with multiple modes of regulation of this highly expressed gene (4). Whereas the proximal promoter serves the function of maintaining the normal cytoskeletal actin level in all cells, the distal promoter is developmentally regulated in different tissues and at different stages (4).…”

mentioning

confidence: 99%

“…But the presence of two promoters provides the organism with multiple modes of regulation of this highly expressed gene (4). Whereas the proximal promoter serves the function of maintaining the normal cytoskeletal actin level in all cells, the distal promoter is developmentally regulated in different tissues and at different stages (4). With such divergent regulatory functions, it is not surprising that the sequences of these two promoters are entirely dissimilar (2,30) except for the presence in both of two putative regulatory elements, GAGA (1, 25) and the serum response element (SRE) (3,18,28).…”

mentioning

confidence: 99%

“…Both iout competitor. It is plotted against the molar ratio of competthe actin SC proximal and distal promoters have a sequence to test plasmid (A) and against the ratio of GAGAs in the CCATATATGG (2,4) identical to the 12-bp core of the ipetitor to those in the test plasmid (B). The latter ratio is based vertebrate SRE that functions in the promoters of c-fos, 20 copies of GAGA in competitor A, 3 copies in competitor B, actin, and other vertebrate genes (28).…”

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confidence: 99%

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Regulatory elements mediating transcription from the Drosophila melanogaster actin 5C proximal promoter.

Chung¹,

Keller²

1990

Mol. Cell. Biol.

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The major cytoskeletal actin gene of Drosophila melanogaster, the actin 5C gene, has two promoters, the proxinal one of which controls constitutive synthesis of actin in all growing tissues. To locate regulatory elements required for constitutive activity of the proximal promoter, mutants of this promoter were fused to the bacterial chloramphenicol acetyltransferase gene and assayed for transient expression activity in cultured Drosophila embryonic Schneider line 2 cells. An essential regulatory element has been located 313 base pairs upstream from the cap site. Deletion of this element lowered expression to one-third of the wild-type level. The element has the sequence AAGTTGTAGTTG, as shown by protein-binding footprinting with the reagent methidiumpropyl-EDTA-Fe(II). This element is probably not a general one, since it was not detected in a search of the published 5'-flanking sequences of 27 Drosophila genes. In addition to this regulatory element, there are five GAGA elements in the actin 5C proximal promoter, some or all of which are essential for the promoter activity as shown by an in vivo competition assay. Although this promoter has no classical TATA element, there is an essential promoter region about 35 base pairs upstream from the cap site that could be a TATA surrogate. The promoter also shows sequences homologous to the alcohol dehydrogenase factor 1-binding site and to the core of the vertebrate serum response element, but mutations of these sites did not affect promoter activity in transient expression assays.The actin SC gene is the major gene in Drosophila melanogaster that encodes the cytoskeletal actin present in all cell types in all growth stages (8-10). The gene is composed of two alternative short leader exons (exons 1 and 2) and a large exon (exon 3) that contains the whole protein-coding region (2, 30). DNA transfection analyses have established that each leader exon is preceded by a separate functional promoter (3). The distal promoter controls the formation of an mRNA composed of exons 1 and 3, and the proximal promoter controls one composed of exons 2 and 3. Since the coding region lies entirely in exon 3, the actin product is the same in both cases. But the presence of two promoters provides the organism with multiple modes of regulation of this highly expressed gene (4). Whereas the proximal promoter serves the function of maintaining the normal cytoskeletal actin level in all cells, the distal promoter is developmentally regulated in different tissues and at different stages (4). With such divergent regulatory functions, it is not surprising that the sequences of these two promoters are entirely dissimilar (2, 30) except for the presence in both of two putative regulatory elements, GAGA (1, 25) and the serum response element (SRE) (3,18,28).This report presents a detailed analysis of the proximal promoter and the elements required for its function. The previous study of Bond-Matthews and Davidson (3) had established that sequences responsible for much of the high activity of this p...

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“…Alternatively, a single gene may possess more than one promoter, different transcripts then coding for the same or different protein products (for a review, see reference 35). The Drosophila Adh (3), actin SC (8), and hunchback (40) genes are examples of genes that have different promoters but whose alternative transcripts code for identical polypeptides. In all of these cases there are both temporal and spatial differences in the expression of the alternative mRNAs.…”

mentioning

confidence: 99%

The Adh gene promoters of Drosophila melanogaster and Drosophila orena are functionally conserved and share features of sequence structure and nuclease-protected sites.

Moses¹,

Heberlein²,

Ashburner³

1990

Mol. Cell. Biol.

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The sibling species Drosophila melanogaster and D. orena show similar patterns of alcohol dehydrogenase expression, both spatially and temporally. These two species diverged from a common ancestor 6 million to 15 million years ago, and the DNA sequences of the promoter regions of their Adh genes show a mosaic pattern of conservation and change. By interspecific transformation of D. orena sequences into D. melanogaster, we demonstrate a functional equivalence between these sequences. Using both D. melanogaster embryo extracts and purified transcription factor Adf-1, we compare the protection of these promoter sequences from nuclease, demonstrating considerable conservation.The transcription of genes by RNA polymerase II is usually regulated by the binding of specific proteins to contiguous DNA sequences. The availability of these transcription factors may determine both the temporal and spatial specificity of transcription of particular genes (for reviews, see references 12, 24, and 27). Different transcription factors may affect the same promoter, affording a mechanism for complex control. This has been seen for several genes in Drosophila melanogaster, including the yolk protein genes (15,29,30), fushi tarazu (19), Hsp26 (10), Ubx (4), and Dopa decarboxylase (7,25). Alternatively, a single gene may possess more than one promoter, different transcripts then coding for the same or different protein products (for a review, see reference 35). The Drosophila Adh (3), actin SC (8), and hunchback (40) genes are examples of genes that have different promoters but whose alternative transcripts code for identical polypeptides. In all of these cases there are both temporal and spatial differences in the expression of the alternative mRNAs. The significance of the complexity in control of these genes is not understood.The two promoters, distal (PD) and proximal (Pp), of the Adh gene of D. melanogaster are about 700 base pairs (bp) apart and encode mRNAs that differ only in their 5' untranslated ends (3, 18; for a review, see reference 36). In D. melanogaster the distal transcript initiates 707 bp 5' to the proximal transcript. The distal primary transcript is spliced to remove a 653-nucleotide intron that includes the sequence of the proximal promoter. Experiments with probes that are specific for either the distal or proximal mRNA have shown that these two RNAs differ in their temporal and spatial expression (23a, 33, 34). Although the unfertilized egg of D. melanogaster inherits from its mother both distal and proximal Adh mRNAs, these have decayed by 3 to 4 h after fertilization. Zygotic expression of Adh begins at about 8 h after fertilization and involves both promoters. The expression-from PD is transient at this stage, and by 12 to 16 h only the proximal mRNA can be detected. This RNA accumulates throughout larval life and is most abundant in the fat body and midgut. A few hours before puparium formation, proximal transcripts disappear; at the same time, a transient * Corresponding author. expression of the distal t...

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Alternative 5C actin transcripts are localized in different patterns during Drosophila embryogenesis

Cited by 44 publications

References 29 publications

Intergenic transcription through a Polycomb group response element counteracts silencing

Intergenic transcription through a Polycomb group response element counteracts silencing

Regulatory elements mediating transcription from the Drosophila melanogaster actin 5C proximal promoter.

The Adh gene promoters of Drosophila melanogaster and Drosophila orena are functionally conserved and share features of sequence structure and nuclease-protected sites.

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