scholarly journals Evolutionary conservation of homeodomain-binding sites and other sequences upstream and within the major transcription unit of the Drosophila segmentation gene engrailed.

1989 ◽  
Vol 9 (10) ◽  
pp. 4304-4311 ◽  
Author(s):  
J A Kassis ◽  
C Desplan ◽  
D K Wright ◽  
P H O'Farrell

The engrailed (en) gene functions throughout Drosophila development and is expressed in a succession of intricate spatial patterns as development proceeds. Normal en function relies on an extremely large cis-acting regulatory region (70 kilobases). We are using evolutionary conservation to help identify en sequences important in regulating patterned expression. Sequence comparison of 2.6 kilobases upstream of the en coding region of D. melanogaster and D. virilis (estimated divergence time, 60 million years) showed that 30% of this DNA occurs in islands of near perfect sequence conservation. One of these conserved islands contains binding sites for homeodomain-containing proteins. It has been shown genetically that homeodomain-containing proteins regulate en expression. Our data suggested that this regulation may be direct. The remaining conserved islands may contain binding sites for other regulatory proteins.

1989 ◽  
Vol 9 (10) ◽  
pp. 4304-4311
Author(s):  
J A Kassis ◽  
C Desplan ◽  
D K Wright ◽  
P H O'Farrell

The engrailed (en) gene functions throughout Drosophila development and is expressed in a succession of intricate spatial patterns as development proceeds. Normal en function relies on an extremely large cis-acting regulatory region (70 kilobases). We are using evolutionary conservation to help identify en sequences important in regulating patterned expression. Sequence comparison of 2.6 kilobases upstream of the en coding region of D. melanogaster and D. virilis (estimated divergence time, 60 million years) showed that 30% of this DNA occurs in islands of near perfect sequence conservation. One of these conserved islands contains binding sites for homeodomain-containing proteins. It has been shown genetically that homeodomain-containing proteins regulate en expression. Our data suggested that this regulation may be direct. The remaining conserved islands may contain binding sites for other regulatory proteins.


Development ◽  
1989 ◽  
Vol 107 (3) ◽  
pp. 575-583 ◽  
Author(s):  
A. Busturia ◽  
J. Casanova ◽  
E. Sanchez-Herrero ◽  
R. Gonzalez ◽  
G. Morata

We report the embryonic and adult phenotypes of a number of mutations of the abd-A gene of the bithorax complex. Some of them result in loss of abd-A function in the whole abd-A domain and are usually lethal. These probably eliminate or inactivate abd-A protein products. Other mutations affect only part of the abd-A domain. These are viable, appear to map outside the abd-A transcription unit, and presumably alter the normal spatial regulation of abd-A products. We propose a model of abd-A structure based on a protein-coding region and two cis-regulatory regions. Regulatory region 1, 3′ to the transcription unit, contains positive and negative regulatory elements. Regulatory region 2, 5′ to the transcription unit, establishes the correct level of abd-A activity in the abdominal metameres.


Development ◽  
1998 ◽  
Vol 125 (8) ◽  
pp. 1469-1476 ◽  
Author(s):  
D. Lessing ◽  
R. Nusse

Patterning of the Drosophila embryo depends on the accurate expression of wingless (wg), which encodes a secreted signal required for segmentation and many other processes. Early expression of wg is regulated by the nuclear proteins of the gap and pair-rule gene classes but, after gastrulation, wg transcription is also dependent on cell-cell communication. Signaling to the Wg-producing cells is mediated by the secreted protein, Hedgehog (Hh), and by Cubitus interruptus (Ci), a transcriptional effector of the Hh signal transduction pathway. The transmembrane protein Patched (Ptc) acts as a negative regulator of wg expression; ptc- embryos have ectopic wg expression. According to the current models, Ptc is a receptor for Hh. The default activity of Ptc is to inhibit Ci function; when Ptc binds Hh, this inhibition is released and Ci can control wg transcription. We have investigated cis-acting sequences that regulate wg during the time that wg expression depends on Hh signaling. We show that approximately 4.5 kb immediately upstream of the wg transcription unit can direct expression of the reporter gene lacZ in domains similar to the normal wg pattern in the embryonic ectoderm. Expression of this reporter construct expands in ptc mutants and responds to hh activity. Within this 4.5 kb, a 150 bp element, highly conserved between D. melanogaster and Drosophila virilis, is required to spatially restrict wg transcription. Activity of this element depends on ptc, but it contains no consensus Ci-binding sites. The discovery of an element that is likely to bind a transcriptional repressor was unexpected, since the prevailing model suggests that wg expression is principally controlled by Hh signaling acting through the Ci activator. We show that wg regulatory DNA can drive lacZ in a proper wg-like pattern without any conserved Ci-binding sites and suggest that Ci can not be the sole endpoint of the Hh pathway.


2003 ◽  
Vol 284 (4) ◽  
pp. R1147-R1150 ◽  
Author(s):  
Ralf Mrowka ◽  
Karola Steinhage ◽  
Andreas Patzak ◽  
Pontus B. Persson

Evolutionary pressure has resulted in the conservation of certain nucleotide sequences. These conserved regions are potentially important for certain functions. Here we give an example of a comparison between noncoding sequences combined with other independent database information to shed light onto the regulation of the renin gene, a gene that has great importance for cardiovascular and renal homeostasis. To combine the information regarding conservation and weight matrices of transcription factor (TF) binding sites, an algorithm was developed (TFprofile). Notably, a local peak in the resulting binding profile coincides with a previously experimentally identified regulatory region for the renin gene. The existence of further peaks in the binding profile in the conserved 3.9-kb-long hRENc DNA block upstream of the renin gene suggests additional regions of potential importance for gene regulation. The algorithm TFprofile may be used to integrate information on cross-species evolutionary conservation and aspects of TF binding characteristics to provide putative regulatory DNA regions for experimental verification.


1996 ◽  
Vol 16 (6) ◽  
pp. 2998-3007 ◽  
Author(s):  
B Kerber ◽  
S Fellert ◽  
H Taubert ◽  
M Hoch

The F elements of Drosophila melanogaster belong to the superfamily of long interspersed nucleotide element retrotransposons. To date, F-element transcription has not been detected in flies. Here we describe the isolation of a member of the F-element family, termed Fex, which is transcribed in specific cells of the female and male germ lines and in various tissues during embryogenesis of D. melanogaster. Sequence analysis revealed that this element contains two complete open reading frames coding for a putative nucleic acid-binding protein and a putative reverse transcriptase. Functional analysis of the 5' region, using germ line transformation of Fex-lacZ reporter gene constructs, demonstrates that major aspects of tissue-specific Fex expression are controlled by internal cis-acting elements that lie in the putative coding region of open reading frame 1. These sequences mediate dynamic gene expression in eight expression domains during embryonic and germ line development. The capacity of the cis-regulatory region of the Fex element to mediate such complex expression patterns is unique among members of the long interspersed nucleotide element superfamily of retrotransposons and is reminiscent of regulatory regions of developmental control genes.


2010 ◽  
Vol 84 (16) ◽  
pp. 8219-8230 ◽  
Author(s):  
Monika Somberg ◽  
Stefan Schwartz

ABSTRACT Our results presented here demonstrate that the most abundant human papillomavirus type 16 (HPV-16) mRNAs expressing the viral oncogenes E6 and E7 are regulated by cellular ASF/SF2, itself defined as a proto-oncogene and overexpressed in cervical cancer cells. We show that the most frequently used 3′-splice site on the HPV-16 genome, site SA3358, which is used to produce primarily E4, E6, and E7 mRNAs, is regulated by ASF/SF2. Splice site SA3358 is immediately followed by 15 potential binding sites for the splicing factor ASF/SF2. Recombinant ASF/SF2 binds to the cluster of ASF/SF2 sites. Mutational inactivation of all 15 sites abolished splicing to SA3358 and redirected splicing to the downstream-located, late 3′-splice site SA5639. Overexpression of a mutant ASF/SF2 protein that lacks the RS domain, also totally inhibited the usage of SA3358 and redirected splicing to the late 3′-splice site SA5639. The 15 ASF/SF2 binding sites could be replaced by an ASF/SF2-dependent, HIV-1-derived splicing enhancer named GAR. This enhancer was also inhibited by the mutant ASF/SF2 protein that lacks the RS domain. Finally, silencer RNA (siRNA)-mediated knockdown of ASF/SF2 caused a reduction in spliced HPV-16 mRNA levels. Taken together, our results demonstrate that the major HPV-16 3′-splice site SA3358 is dependent on ASF/SF2. SA3358 is used by the most abundantly expressed HPV-16 mRNAs, including those encoding E6 and E7. High levels of ASF/SF2 may therefore be a requirement for progression to cervical cancer. This is supported by our earlier findings that ASF/SF2 is overexpressed in high-grade cervical lesions and cervical cancer.


1989 ◽  
Vol 9 (8) ◽  
pp. 3517-3523
Author(s):  
D P McDonnell ◽  
J W Pike ◽  
D J Drutz ◽  
T R Butt ◽  
B W O'Malley

The human osteocalcin gene is regulated in mammalian osteoblasts by 1,25(OH)2D3-dependent and -independent mechanisms. The sequences responsible for this activity have been mapped to within the -1339 region of the gene. We show here that this enhancer region functions analogously in Saccharomyces cerevisiae cells engineered to produce active 1,25(OH)2D3 receptor. When fused to the proximal promoter elements of the yeast iso-1-cytochrome c gene, the enhancer demonstrated substantial promoter activity. This activity was elevated further by 1,25(OH)2D3 when the reporter constructs were assayed in cells containing the 1,25(OH)2D3 receptor. This system affords a model for 1,25(OH)2D3 action and represents a simple assay system that will enable definition of the important cis-acting regulatory sequences within the osteocalcin gene and identification of their cognate transcription factors.


2021 ◽  
Vol 118 (42) ◽  
pp. e2110887118
Author(s):  
Qiang Wang ◽  
Lin Zhang ◽  
Guo-Wei Zhang ◽  
Jian-Hua Mao ◽  
Xiao-Dong Xi ◽  
...  

Infusing CRISPR/donor-loaded adeno-associated viral vectors (AAV/CRISPR) could enable in vivo hepatic gene editing to remedy hemophilia B (HB) with inherited deficiency of clotting factor IX (FIX). Yet, current regimens focus on correcting HB with simple mutations in the coding region of the F9, overlooking those carrying complicated mutations involving the regulatory region. Moreover, a possible adverse effect of treatment-related inflammation remains unaddressed. Here we report that a single DNA cutting-mediated long-range replacement restored the FIX-encoding function of a mutant F9 (mF9) carrying both regulatory and coding defects in a severe mouse HB model, wherein incorporation of a synthetic Alb enhancer/promoter-mimic (P2) ensured FIX elevation to clinically meaningful levels. Through single-cell RNA sequencing (scRNA-seq) of liver tissues, we revealed that a subclinical hepatic inflammation post-AAV/CRISPR administration regulated the vulnerability of the edited mF9-harboring host cells to cytotoxic T lymphocytes (CTLs) and the P2 activity in a hepatocytic subset–dependent manner via modulating specific sets of liver-enriched transcription factors (LETFs). Collectively, our study establishes an AAV/CRISPR-mediated gene-editing protocol applicable to complicated monogenetic disorders, underscoring the potentiality of improving therapeutic benefits through managing inflammation.


1989 ◽  
Vol 9 (11) ◽  
pp. 4621-4630
Author(s):  
D J Mahoney ◽  
J R Broach

Mating-type genes resident in the silent cassette HML at the left arm of chromosome III are repressed by the action of four SIR gene products, most likely mediated through two cis-acting sites located on opposite sides of the locus. We showed that deletion of either of these two cis-acting sites from the chromosome did not yield any detectable derepression of HML, while deletion of both sites yielded full expression of the locus. In addition, each of these sites was capable of exerting repression of heterologous genes inserted in their vicinity. Thus, HML expression is regulated by two independent silencers, each fully competent for maintaining repression. This situation was distinct from the organization of the other silent locus, HMR, at which a single silencer served as the predominant repressor of expression. Examination of identifiable domains and binding sites within the HML silencers suggested that silencing activity can be achieved by a variety of combinations of various functional domains.


2016 ◽  
Vol 44 (14) ◽  
pp. 6883-6895 ◽  
Author(s):  
Andrew Woodman ◽  
Jamie J. Arnold ◽  
Craig E. Cameron ◽  
David J. Evans

Abstract Genetic recombination in single-strand, positive-sense RNA viruses is a poorly understand mechanism responsible for generating extensive genetic change and novel phenotypes. By moving a critical cis-acting replication element (CRE) from the polyprotein coding region to the 3′ non-coding region we have further developed a cell-based assay (the 3′CRE-REP assay) to yield recombinants throughout the non-structural coding region of poliovirus from dually transfected cells. We have additionally developed a defined biochemical assay in which the only protein present is the poliovirus RNA dependent RNA polymerase (RdRp), which recapitulates the strand transfer events of the recombination process. We have used both assays to investigate the role of the polymerase fidelity and nucleotide turnover rates in recombination. Our results, of both poliovirus intertypic and intratypic recombination in the CRE-REP assay and using a range of polymerase variants in the biochemical assay, demonstrate that RdRp fidelity is a fundamental determinant of recombination frequency. High fidelity polymerases exhibit reduced recombination and low fidelity polymerases exhibit increased recombination in both assays. These studies provide the basis for the analysis of poliovirus recombination throughout the non-structural region of the virus genome and provide a defined biochemical assay to further dissect this important evolutionary process.


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