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An engaging examination of Black Girl Magic and its significance in American literature In Light and Legacies , author Janaka Bowman Lewis examines Black girlhood in American literature from the mid-twentieth century to the present. The representation of Black girlhood in contemporary literature has long remained underexplored. Through this literary history of \"Black Girl Magic,\" Lewis offers one of the first studies in this rapidly growing field of study. Light and Legacies poignantly showcases the activist dimensions of creative literature through work by women writers such as Toni Morrison and Toni Cade. As vectors of protest, these stories reflect historical events while also creating an enduring space of liberation and expression. The book provides didactic and reflective portrayals of the Black experience-an experience that has long been misunderstood. In a work both enlightening and personal, Lewis brilliantly weaves accounts of her own journey together with the liberating stories that shaped her and so many others.

RNA silencing is a highly conserved pathway in the network of interconnected defense responses that are activated during viral infection. As a counter-defense, many plant viruses encode proteins that block silencing, often also interfering with endogenous small RNA pathways. However, the mechanism of action of viral suppressors is not well understood and the role of host factors in the process is just beginning to emerge. Here we report that the ethylene-inducible transcription factor RAV2 is required for suppression of RNA silencing by two unrelated plant viral proteins, potyvirus HC-Pro and carmovirus P38. Using a hairpin transgene silencing system, we find that both viral suppressors require RAV2 to block the activity of primary siRNAs, whereas suppression of transitive silencing is RAV2-independent. RAV2 is also required for many HC-Pro-mediated morphological anomalies in transgenic plants, but not for the associated defects in the microRNA pathway. Whole genome tiling microarray experiments demonstrate that expression of genes known to be required for silencing is unchanged in HC-Pro plants, whereas a striking number of genes involved in other biotic and abiotic stress responses are induced, many in a RAV2-dependent manner. Among the genes that require RAV2 for induction by HC-Pro are FRY1 and CML38, genes implicated as endogenous suppressors of silencing. These findings raise the intriguing possibility that HC-Pro-suppression of silencing is not caused by decreased expression of genes that are required for silencing, but instead, by induction of stress and defense responses, some components of which interfere with antiviral silencing. Furthermore, the observation that two unrelated viral suppressors require the activity of the same factor to block silencing suggests that RAV2 represents a control point that can be readily subverted by viruses to block antiviral silencing.

Dicer-like (DCL) enzymes play a pivotal role in RNA silencing in plants, processing the long double-stranded RNA (dsRNA) that triggers silencing into the primary short interfering RNAs (siRNAs) that mediate it. The siRNA population can be augmented and silencing amplified via transitivity, an RNA-dependent RNA polymerase (RDR)-dependent pathway that uses the target RNA as substrate to generate secondary siRNAs. Here we report that Arabidopsis DCL2-but not DCL4-is required for transitivity in cell-autonomous, post-transcriptional silencing of transgenes. An insertion mutation in DCL2 blocked sense transgene-induced silencing and eliminated accumulation of the associated RDR-dependent siRNAs. In hairpin transgene-induced silencing, the dcl2 mutation likewise eliminated accumulation of secondary siRNAs and blocked transitive silencing, but did not block silencing mediated by primary siRNAs. Strikingly, in all cases, the dcl2 mutation eliminated accumulation of all secondary siRNAs, including those generated by other DCL enzymes. In contrast, mutations in DCL4 promoted a dramatic shift to transitive silencing in the case of the hairpin transgene and enhanced silencing induced by the sense transgene. Suppression of hairpin and sense transgene silencing by the P1/HC-Pro and P38 viral suppressors was associated with elimination of secondary siRNA accumulation, but the suppressors did not block processing of the stem of the hairpin transcript into primary siRNAs. Thus, these viral suppressors resemble the dcl2 mutation in their effects on siRNA biogenesis. We conclude that DCL2 plays an essential, as opposed to redundant, role in transitive silencing of transgenes and may play a more important role in silencing of viruses than currently thought.

Two major classes of small noncoding RNAs have emerged as important regulators of gene expression in eukaryotes, the short interfering RNAs (siRNAs) associated with RNA silencing and endogenous micro-RNAs (miRNAs) implicated in regulation of gene expression. Helper component-proteinase (HC-Pro) is a viral protein that blocks RNA silencing in plants. Here we examine the effect of HC-Pro on the accumulation of siRNAs and endogenous miRNAs. siRNAs were analyzed in transgenic tobacco plants silenced in response to three different classes of transgenes: sense-transgenes, inverted-repeat transgenes, and amplicon-transgenes. HC-Pro suppressed silencing in each line, blocking accumulation of the associated siRNAs and allowing accumulation of transcripts from the previously silenced loci. HC-Pro-suppression of silencing in the inverted-repeat- and amplicon-transgenic lines was accompanied by the apparent accumulation of long double-stranded RNAs and proportional amounts of small RNAs that are larger than the siRNAs that accumulate during silencing. Analysis of these results suggests that HC-Pro interferes with silencing either by inhibiting siRNA processing from double-stranded RNA precursors or by destabilizing siRNAs. In contrast to siRNAs, the accumulation of endogenous miRNAs was greatly enhanced in all of the HC-Pro-expressing lines. Thus, our results demonstrate that accumulation of siRNAs and miRNAs in plants can be differentially regulated by a viral protein. The fact that HC-Pro affects the miRNA pathway raises the possibility that this pathway is targeted by plant viruses as a means to control gene expression in the host.

Many biotechnological applications require high-level expression of transgenes in plants. One strategy to achieve this goal was the production of potato virus X (PVX) “amplicon” lines: transgenic lines that encode a replicating RNA virus vector carrying a gene of interest 1 . The idea was that transcription of the amplicon transgene would initiate viral RNA replication and gene expression, resulting in very high levels of the gene product of interest. This approach failed, however, because every amplicon transgene, in both tobacco and Arabidopsis thaliana , was subject to post-transcriptional gene silencing (PTGS) 1 , 2 , 3 . In PTGS, the transgene is transcribed but the transcripts fail to accumulate as a result of sequence-specific targeting and destruction 4 , 5 . Even though the amplicon locus is silenced, the level of β-glucuronidase (GUS) activity in a PVX/GUS line is similar to that in some transgenic lines expressing GUS from a conventional (not silenced) GUS locus 1 . This result suggested that the very high levels of expression originally envisioned for amplicons could be achieved if PTGS could be overcome and if the resulting plants did not suffer from severe viral disease. Here we report that high-level transgene expression can be achieved by pairing the amplicon approach with the use of a viral suppressor of PTGS, tobacco etch virus (TEV) helper component–proteinase (HC-Pro). Leaves of mature tobacco plants co-expressing HC-Pro and a PVX/GUS amplicon accumulate GUS to ∼3% of total protein. Moreover, high-level expression occurs without viral symptoms and, when HC-Pro is expressed from a mutant transgene, without detrimental developmental phenotypes.

Expression of the viral silencing suppressor P1/HC-Pro in plants causes severe developmental anomalies accompanied by defects in both short interfering RNA (siRNA) and microRNA (miRNA) pathways. P1/HC-Pro transgenic lines fail to accumulate the siRNAs that mediate RNA silencing and are impaired in both miRNA processing and function, accumulating abnormally high levels of miRNA/miRNA* processing intermediates as well as miRNA target messages. Both miRNA and RNA silencing pathways require participation of DICER-LIKE (DCL) ribonuclease III-like enzymes. Here, we investigate the effects of overexpressing DCL1, one of four Dicers in Arabidopsis thaliana, on P1/HC-Pro-induced defects in development and small RNA metabolism. Expression of a DCL1 cDNA transgene (35S:DCL1) produced a mild gain-of-function phenotype and largely rescued dcl1 mutant phenotypes. The 35S:DCL1 plants were competent for virus-induced RNA silencing but were impaired in transgene-induced RNA silencing and in the accumulation of some miRNAs. Ectopic DCL1 largely alleviated developmental anomalies in P1/HC-Pro plants but did not correct the P1/HC-Pro-associated defects in small RNA pathways. The ability of P1/HC-Pro plants to suppress RNA silencing and the levels of miRNAs, miRNA*s, and miRNA target messages in these plants were essentially unaffected by ectopic DCL1. These data suggest that P1/HC-Pro defects in development do not result from general impairments in small RNA pathways and raise the possibility that DCL1 participates in processes in addition to miRNA biogenesis.

Normal 0 false false false MicrosoftInternetExplorer4 There is widespread agreement that the South has changed dramatically since the end of World War II. Social, demographic, economic, and political changes have altered significantly the region long considered the nation’s most distinctive. There is less agreement, however, about the extent to which the forces of nationalization have eroded the major elements of Southern distinctiveness. Although this volume does not purport to settle the debate on Southern political change, it does present a variety of recent evidence that helps put this important debate into perspective. In the process it helps clarify the contemporary politics of the South for readers ranging from the scholar to the more casual observer. The essays in The Disappearing South address the ongoing debate. Contributors, in addition to the editors, include E. Lee Bernick, Earl Black, Merle Black, Lewis Bowman, Edward G. Carmines, Patrick Cotter, Thomas Eamon, Douglas G. Feig, John C. Green, James L. Guth, William E. Hulbary, Anne E. Kelley, Lyman A. Kellstedt, David M. Olson, John Shelton Reed, Harold Stanley, James G. Stovall, John Theilmann, Stephen H. Wainscott, and Allen Wilhite.  

These new essays map the ways political parties remain vital components in the American political system, especially in the eleven states in the South. As Tocqueville noted more than 100 years ago, "No countries need associations more . . . than those with a democratic social state." Although some contemporary observers see a decline in associations, especially in the political sphere, the contributors in this volume argue not only that political parties remain an essential component of the American political system but also that grassroots political groups have revitalized the political process, especially in the South. Using data gathered from local party officials in the eleven southern states, the authors examine such key issues as: Who becomes involved in local party organizations and why? How do parties recruit and retain workers? What are the ideological and issue orientations of these activists? How does intraparty factionalism affect local party organizations? What is the connection between the party organization and its external environment? The large regional database provides these contributors with the opportunity to extend the study of local party organization and activists, thus addressing some of the significant gaps in previous research. The additional data enable them to clarify the nature of local party organizations and, in a larger sense, the role of the parties in the contemporary American political system.