A maize MuDR transposon promoter shows limited autoregulation

Raizada, Manish N.; Brewer, K.V.; Walbot, Virginia

doi:10.1007/s004380000393

Cited by 20 publications

(14 citation statements)

References 27 publications

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“…Consequently, it appears that MuDRderived products modulate either hMuDR transcription or transcript half-life. A similar conclusion was reached in a transgenic maize experiment in which the expression of ␤-glucuronidase and luciferase transgenes under the control of the mudrB TIR promoter was transiently and modestly increased by the presence of a transcriptionally active MuDR element (Raizada et al, 2001b). These authors proposed that MURA may protect TIRs from host methylation and thus indirectly increase transcription from elements with related promoters.…”

Section: Mudr and Hmudr Transcriptssupporting

confidence: 55%

Expression and Post-Transcriptional Regulation of Maize Transposable Element MuDR and Its Derivatives

Rudenko¹,

Walbot²

2001

The Plant Cell

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The transposition of Mu elements underlying Mutator activity in maize requires a transcriptionally active MuDR element. Despite variation in MuDR copy number and RNA levels in Mutator lines, transposition events are consistently late in plant development, and Mu excision frequencies are similar. Here, we report previously unsuspected and ubiquitous MuDR homologs that produce both RNA and protein. MuDR transcript levels are proportional to MuDR copy number, and homolog transcript levels increase in active Mutator lines. A subset of homologs exhibits constitutive transcription in MuDR Ϫ and epigenetically silenced MuDR lines, suggesting independent transcriptional regulation. Surprisingly, immunodetection demonstrated nearly invariant levels of MuDR and homolog protein products in all tested Mutator and non-Mutator stocks. These results suggest a strict control over protein production, which might explain the uniform excision frequency of Mu elements. Moreover, the nonfunctional proteins encoded by homologs may negatively regulate Mutator activity and represent part of the host defense against this transposon family. INTRODUCTIONOptimized transmission and restricted transposition activity are characteristics of many transposable elements. These features combine to allow efficient transposon proliferation with a minimal cost to the host genome. A variety of regulatory mechanisms operating at both the transcriptional and post-transcriptional levels can result in specific temporal and spatial patterns of transposon activity. Some mechanisms are epigenetic and act through several generations. In plants, increased DNA methylation of promoter regions of autonomous elements such as Ac , En / Spm , and MuDR correlates with decreased production of transposase transcripts and loss of transposition reactions (Fedoroff and Chandler, 1994; Martienssen and Baron, 1994). In some cases, host methylation acts in concert with transposon autoregulation. For example, the TnpA transposase protein encoded by Spm binds to its own unmethylated promoter, an interaction that decreases transcription; in the absence of Spm -encoded products, the promoter becomes methylated, and both transcription and transposition cease (Schläppi et al., 1994). Introduction of a functional Spm element results in activation of the silenced promoter and resumption of transposon activity.More dynamic regulation occurs during a single life cycle to limit the production or function of active transposase proteins.For example, tissue-specific RNA splicing restricts expression of the functional transposase of the Drosophila melanogaster P element to the germ line (Laski et al., 1986;Siebel et al., 1992). In bacteria, the inhibition of bacterial Tn10 transposition occurs through production of element-encoded antisense RNA (Simons and Kleckner, 1988). The maize transposable element Ac exhibits a negative dosage phenomenon: with increasing copy number and RNA levels, there is a lower excision frequency, and transposition events occur later in development (McClintock, 1...

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Section: Mudr and Hmudr Transcriptssupporting

confidence: 55%

Expression and Post-Transcriptional Regulation of Maize Transposable Element MuDR and Its Derivatives

Rudenko¹,

Walbot²

2001

The Plant Cell

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“…44,45 Another TE, the Hat element, derived an insulated protein (BEAF-32 of Drosophila) that connects the specialized chromatin structure to the adjacent chromatin elements and the nuclear matrix. 46 Other degenerate TE sequences, such as miniature inverted-repeat transposable elements (MITEs), are often transcribed and contain terminal inverted repeats.…”

Section: Discussionmentioning

confidence: 99%

Construction and Characterization of a Repetitive DNA Library in Parodontidae (Actinopterygii: Characiformes): A Genomic and Evolutionary Approach to the Degeneration of the W Sex Chromosome

et al. 2014

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Repetitive DNA sequences, including tandem and dispersed repeats, comprise a large portion of eukaryotic genomes and are important for gene regulation, sex chromosome differentiation, and karyotype evolution. In Parodontidae, only the repetitive DNAs WAp and pPh2004 and rDNAs were previously studied using fluorescence in situ hybridization. This study aimed to build a library of repetitive DNA in Parodontidae. We isolated 40 clones using C o t-1; 17 of these clones exhibited similarity to repetitive DNA sequences, including satellites, minisatellites, microsatellites, and class I and class II transposable elements (TEs), from Danio rerio and other organisms. The physical mapping of the clones to chromosomes revealed the presence of a satellite DNA, a Helitron element, and degenerate short interspersed element (SINE), long interspersed element (LINE), and tc1-mariner elements on the sex chromosomes. Some clones exhibited dispersed signals; other sequences were not detected. The 5S rDNA was detected on an autosomal pair. These elements likely function in the molecular degeneration of the W chromosome in Parodontidae. Thus, the location of these elements on the chromosomes is important for understanding the function of these repetitive DNAs and for integrative studies with genome sequencing. The presented data demonstrate that an intensive invasion of TEs occurred during W sex chromosome differentiation in the Parodontidae.

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“…Interestingly, several different classes of transposases (such as MURA and TnpA, one of the two transposase proteins encoded by the maize Spm transposon) are known to function as transcriptional regulators that regulate their own expression (Raizada et al, 2001;Cui and Fedoroff, 2002). For example, Raizada et al (2001) observed that active MuDR elements increase the expression of a LUC reporter gene driven by its terminal inverted repeat promoter by 2-to 10-fold, and they proposed that MURA may act as a weak transcriptional activator. Similarly, the transposase encoded by the maize Activator (Ac) transposable element has been shown to repress the Ac transposase gene promoter (a form of element "self-repression") as well as nontransposable element promoters (Fridlender et al, 1996;MacRae, 2002).…”

Section: Discrete and Essential Roles Of The Multiple Domains Of Fhy3mentioning

confidence: 99%

Discrete and Essential Roles of the Multiple Domains of Arabidopsis FHY3 in Mediating Phytochrome A Signal Transduction

et al. 2008

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Phytochrome A is the primary photoreceptor for mediating various far-red light-induced responses in higher plants. We recently showed that Arabidopsis (Arabidopsis thaliana) FAR-RED ELONGATED HYPOCOTYL3 (FHY3) and FAR-RED-IMPAIRED RESPONSE1 (FAR1), a pair of homologous proteins sharing significant sequence homology to Mutator-like transposases, act as novel transcription factors essential for activating the expression of FHY1 and FHL (for FHY1-like), whose products are required for light-induced phytochrome A nuclear accumulation and subsequent light responses. FHY3, FAR1, and Mutator-like transposases also share a similar domain structure, including an N-terminal C2H2 zinc finger domain, a central putative core transposase domain, and a C-terminal SWIM motif (named after SWI2/SNF and MuDR transposases). In this study, we performed a promoter-swapping analysis of FHY3 and FAR1. Our results suggest that the partially overlapping functions of FHY3 and FAR1 entail divergence of their promoter activities and protein subfunctionalization. To gain a better understanding of the molecular mode of FHY3 function, we performed a structure-function analysis, using site-directed mutagenesis and transgenic approaches. We show that the conserved N-terminal C2H2 zinc finger domain is essential for direct DNA binding and biological function of FHY3 in mediating light signaling, whereas the central core transposase domain and C-terminal SWIM domain are essential for the transcriptional regulatory activity of FHY3 and its homodimerization or heterodimerization with FAR1. Furthermore, the ability to form homodimers or heterodimers largely correlates with the transcriptional regulatory activity of FHY3 in plant cells. Together, our results reveal discrete roles of the multiple domains of FHY3 and provide functional support for the proposition that FHY3 and FAR1 represent transcription factors derived from a Mutator-like transposase(s).

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A maize MuDR transposon promoter shows limited autoregulation

Cited by 20 publications

References 27 publications

Expression and Post-Transcriptional Regulation of Maize Transposable Element MuDR and Its Derivatives

Expression and Post-Transcriptional Regulation of Maize Transposable Element MuDR and Its Derivatives

Construction and Characterization of a Repetitive DNA Library in Parodontidae (Actinopterygii: Characiformes): A Genomic and Evolutionary Approach to the Degeneration of the W Sex Chromosome

Discrete and Essential Roles of the Multiple Domains of Arabidopsis FHY3 in Mediating Phytochrome A Signal Transduction

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