{"title":"Cell Size Control in Plants.","authors":"Marco D'Ario, R. Sablowski","doi":"10.1146/annurev-genet-112618-043602","DOIUrl":"https://doi.org/10.1146/annurev-genet-112618-043602","url":null,"abstract":"The genetic control of the characteristic cell sizes of different species and tissues is a long-standing enigma. Plants are convenient for studying this question in a multicellular context, as their cells do not move and are easily tracked and measured from organ initiation in the meristems to subsequent morphogenesis and differentiation. In this article, we discuss cell size control in plants compared with other organisms. As seen from yeast cells to mammalian cells, size homeostasis is maintained cell autonomously in the shoot meristem. In developing organs, vacuolization contributes to cell size heterogeneity and may resolve conflicts between growth control at the cellular and organ levels. Molecular mechanisms for cell size control have implications for how cell size responds to changes in ploidy, which are particularly important in plant development and evolution. We also discuss comparatively the functional consequences of cell size and their potential repercussions at higher scales, including genome evolution. Expected final online publication date for the Annual Review of Genetics, Volume 53 is November 23, 2019. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8035,"journal":{"name":"Annual review of genetics","volume":" ","pages":""},"PeriodicalIF":11.1,"publicationDate":"2019-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1146/annurev-genet-112618-043602","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46000205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Zebrafish Pigment Pattern Formation: Insights into the Development and Evolution of Adult Form.","authors":"Larissa B. Patterson, D. Parichy","doi":"10.1146/annurev-genet-112618-043741","DOIUrl":"https://doi.org/10.1146/annurev-genet-112618-043741","url":null,"abstract":"Vertebrate pigment patterns are diverse and fascinating adult traits that offer protection from the environment and allow animals to attract mates and avoid predators. Pigment patterns in fish are among the most amenable traits for studying the cellular basis of adult form, as the cells that produce diverse patterns are readily visible in the skin during development. The genetic basis of pigment pattern development has been most studied in the zebrafish, Danio rerio. Zebrafish adults have alternating dark and light horizontal stripes, resulting from the precise arrangement of three main classes of pigment cells: black melanophores, yellow xanthophores, and iridescent iridophores. The coordination of adult pigment cell lineage specification and differentiation with specific cellular interactions and morphogenetic behaviors is necessary for stripe development. Besides providing a nice example of pattern formation responsible for an adult trait of zebrafish, stripe-forming mechanisms also provide a conceptual framework for posing testable hypotheses about pattern diversification more broadly. Here, we summarize what is known about lineages and molecular interactions required for pattern formation in zebrafish, we review some of what is known about pattern diversification in Danio, and we speculate on how patterns in more distant teleosts may have evolved to produce a stunningly diverse array of patterns in nature. Expected final online publication date for the Annual Review of Genetics, Volume 53 is November 23, 2019. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8035,"journal":{"name":"Annual review of genetics","volume":" ","pages":""},"PeriodicalIF":11.1,"publicationDate":"2019-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1146/annurev-genet-112618-043741","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48743152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Mechanisms of DNA Uptake by Naturally Competent Bacteria.","authors":"David Dubnau, Melanie Blokesch","doi":"10.1146/annurev-genet-112618-043641","DOIUrl":"https://doi.org/10.1146/annurev-genet-112618-043641","url":null,"abstract":"<p><p>Transformation is a widespread mechanism of horizontal gene transfer in bacteria. DNA uptake to the periplasmic compartment requires a DNA-uptake pilus and the DNA-binding protein ComEA. In the gram-negative bacteria, DNA is first pulled toward the outer membrane by retraction of the pilus and then taken up by binding to periplasmic ComEA, acting as a Brownian ratchet to prevent backward diffusion. A similar mechanism probably operates in the gram-positive bacteria as well, but these systems have been less well characterized. Transport, defined as movement of a single strand of transforming DNA to the cytosol, requires the channel protein ComEC. Although less is understood about this process, it may be driven by proton symport. In this review we also describe various phenomena that are coordinated with the expression of competence for transformation, such as fratricide, the kin-discriminatory killing of neighboring cells, and competence-mediated growth arrest.</p>","PeriodicalId":8035,"journal":{"name":"Annual review of genetics","volume":"53 ","pages":"217-237"},"PeriodicalIF":11.1,"publicationDate":"2019-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1146/annurev-genet-112618-043641","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9301235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Genetic Factors in Mammalian Prion Diseases.","authors":"S. Mead, S. Lloyd, J. Collinge","doi":"10.1146/annurev-genet-120213-092352","DOIUrl":"https://doi.org/10.1146/annurev-genet-120213-092352","url":null,"abstract":"Mammalian prion diseases are a group of neurodegenerative conditions caused by infection of the central nervous system with proteinaceous agents called prions, including sporadic, variant, and iatrogenic Creutzfeldt-Jakob disease; kuru; inherited prion disease; sheep scrapie; bovine spongiform encephalopathy; and chronic wasting disease. Prions are composed of misfolded and multimeric forms of the normal cellular prion protein (PrP). Prion diseases require host expression of the prion protein gene (PRNP) and a range of other cellular functions to support their propagation and toxicity. Inherited forms of prion disease are caused by mutation of PRNP, whereas acquired and sporadically occurring mammalian prion diseases are controlled by powerful genetic risk and modifying factors. Whereas some PrP amino acid variants cause the disease, others confer protection, dramatically altered incubation times, or changes in the clinical phenotype. Multiple mechanisms, including interference with homotypic protein interactions and the selection of the permissible prion strains in a host, play a role. Several non-PRNP factors have now been uncovered that provide insights into pathways of disease susceptibility or neurotoxicity. Expected final online publication date for the Annual Review of Genetics, Volume 53 is November 23, 2019. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8035,"journal":{"name":"Annual review of genetics","volume":" ","pages":""},"PeriodicalIF":11.1,"publicationDate":"2019-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1146/annurev-genet-120213-092352","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46532256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The foraging Gene and Its Behavioral Effects: Pleiotropy and Plasticity.","authors":"I. Anreiter, M. Sokolowski","doi":"10.1146/annurev-genet-112618-043536","DOIUrl":"https://doi.org/10.1146/annurev-genet-112618-043536","url":null,"abstract":"The Drosophila melanogaster foraging ( for) gene is a well-established example of a gene with major effects on behavior and natural variation. This gene is best known for underlying the behavioral strategies of rover and sitter foraging larvae, having been mapped and named for this phenotype. Nevertheless, in the last three decades an extensive array of studies describing for's role as a modifier of behavior in a wide range of phenotypes, in both Drosophila and other organisms, has emerged. Furthermore, recent work reveals new insights into the genetic and molecular underpinnings of how for affects these phenotypes. In this article, we discuss the history of the for gene and its role in natural variation in behavior, plasticity, and behavioral pleiotropy, with special attention to recent findings on the molecular structure and transcriptional regulation of this gene. Expected final online publication date for the Annual Review of Genetics, Volume 53 is November 23, 2019. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8035,"journal":{"name":"Annual review of genetics","volume":" ","pages":""},"PeriodicalIF":11.1,"publicationDate":"2019-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1146/annurev-genet-112618-043536","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45027967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Light in the Fungal World: From Photoreception to Gene Transcription and Beyond.","authors":"L. Corrochano","doi":"10.1146/annurev-genet-120417-031415","DOIUrl":"https://doi.org/10.1146/annurev-genet-120417-031415","url":null,"abstract":"Fungi see light of different colors by using photoreceptors such as the White Collar proteins and cryptochromes for blue light, opsins for green light, and phytochromes for red light. Light regulates fungal development, promotes the accumulation of protective pigments and proteins, and regulates tropic growth. The White Collar complex (WCC) is a photoreceptor and a transcription factor that is responsible for regulating transcription after exposure to blue light. In Neurospora crassa, light promotes the interaction of WCCs and their binding to the promoters to activate transcription. In Aspergillus nidulans, the WCC and the phytochrome interact to coordinate gene transcription and other responses, but the contribution of these photoreceptors to fungal photobiology varies across fungal species. Ultimately, the effect of light on fungal biology is the result of the coordinated transcriptional regulation and activation of signal transduction pathways. Expected final online publication date for the Annual Review of Genetics, Volume 53 is November 23, 2019. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8035,"journal":{"name":"Annual review of genetics","volume":" ","pages":""},"PeriodicalIF":11.1,"publicationDate":"2019-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1146/annurev-genet-120417-031415","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43593626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Evolutionary Ecology of Wolbachia Releases for Disease Control.","authors":"Perran A. Ross, M. Turelli, A. Hoffmann","doi":"10.1146/annurev-genet-112618-043609","DOIUrl":"https://doi.org/10.1146/annurev-genet-112618-043609","url":null,"abstract":"Wolbachia is an endosymbiotic Alphaproteobacteria that can suppress insect-borne diseases through decreasing host virus transmission (population replacement) or through decreasing host population density (population suppression). We contrast natural Wolbachia infections in insect populations with Wolbachia transinfections in mosquitoes to gain insights into factors potentially affecting the long-term success of Wolbachia releases. Natural Wolbachia infections can spread rapidly, whereas the slow spread of transinfections is governed by deleterious effects on host fitness and demographic factors. Cytoplasmic incompatibility (CI) generated by Wolbachia is central to both population replacement and suppression programs, but CI in nature can be variable and evolve, as can Wolbachia fitness effects and virus blocking. Wolbachia spread is also influenced by environmental factors that decrease Wolbachia titer and reduce maternal Wolbachia transmission frequency. More information is needed on the interactions between Wolbachia and host nuclear/mitochondrial genomes, the interaction between invasion success and local ecological factors, and the long-term stability of Wolbachia-mediated virus blocking. Expected final online publication date for the Annual Review of Genetics, Volume 53 is November 23, 2019. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8035,"journal":{"name":"Annual review of genetics","volume":" ","pages":""},"PeriodicalIF":11.1,"publicationDate":"2019-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1146/annurev-genet-112618-043609","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48052406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Liquid-Liquid Phase Separation in Disease.","authors":"S. Alberti, D. Dormann","doi":"10.1146/annurev-genet-112618-043527","DOIUrl":"https://doi.org/10.1146/annurev-genet-112618-043527","url":null,"abstract":"We have made rapid progress in recent years in identifying the genetic causes of many human diseases. However, despite this recent progress, our mechanistic understanding of these diseases is often incomplete. This is a problem because it limits our ability to develop effective disease treatments. To overcome this limitation, we need new concepts to describe and comprehend the complex mechanisms underlying human diseases. Condensate formation by phase separation emerges as a new principle to explain the organization of living cells. In this review, we present emerging evidence that aberrant forms of condensates are associated with many human diseases, including cancer, neurodegeneration, and infectious diseases. We examine disease mechanisms driven by aberrant condensates, and we point out opportunities for therapeutic interventions. We conclude that phase separation provides a useful new framework to understand and fight some of the most severe human diseases. Expected final online publication date for the Annual Review of Genetics, Volume 53 is November 23, 2019. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8035,"journal":{"name":"Annual review of genetics","volume":" ","pages":""},"PeriodicalIF":11.1,"publicationDate":"2019-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1146/annurev-genet-112618-043527","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45398037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Arms Race Between KRAB-Zinc Finger Proteins and Endogenous Retroelements and Its Impact on Mammals.","authors":"Melania Bruno, M. Mahgoub, T. Macfarlan","doi":"10.1146/annurev-genet-112618-043717","DOIUrl":"https://doi.org/10.1146/annurev-genet-112618-043717","url":null,"abstract":"Nearly half of the human genome consists of endogenous retroelements (EREs) and their genetic remnants, a small fraction of which carry the potential to propagate in the host genome, posing a threat to genome integrity and cell/organismal survival. The largest family of transcription factors in tetrapods, the Krüppel-associated box domain zinc finger proteins (KRAB-ZFPs), binds to specific EREs and represses their transcription. Since their first appearance over 400 million years ago, KRAB-ZFPs have undergone dramatic expansion and diversification in mammals, correlating with the invasions of new EREs. In this article we review our current understanding of the structure, function, and evolution of KRAB-ZFPs and discuss growing evidence that the arms race between KRAB-ZFPs and the EREs they target is a major driving force for the evolution of new traits in mammals, often accompanied by domestication of EREs themselves. Expected final online publication date for the Annual Review of Genetics, Volume 53 is November 23, 2019. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8035,"journal":{"name":"Annual review of genetics","volume":" ","pages":""},"PeriodicalIF":11.1,"publicationDate":"2019-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1146/annurev-genet-112618-043717","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42910724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Christopher J. Bohlen, Brad A. Friedman, Borislav Dejanovic, Morgan Sheng
{"title":"Microglia in Brain Development, Homeostasis, and Neurodegeneration.","authors":"Christopher J. Bohlen, Brad A. Friedman, Borislav Dejanovic, Morgan Sheng","doi":"10.1146/annurev-genet-112618-043515","DOIUrl":"https://doi.org/10.1146/annurev-genet-112618-043515","url":null,"abstract":"Advances in human genetics have implicated a growing number of genes in neurodegenerative diseases, providing insight into pathological processes. For Alzheimer disease in particular, genome-wide association studies and gene expression studies have emphasized the pathogenic contributions from microglial cells and motivated studies of microglial function/dysfunction. Here, we summarize recent genetic evidence for microglial involvement in neurodegenerative disease with a focus on Alzheimer disease, for which the evidence is most compelling. To provide context for these genetic discoveries, we discuss how microglia influence brain development and homeostasis, how microglial characteristics change in disease, and which microglial activities likely influence the course of neurodegeneration. In all, we aim to synthesize varied aspects of microglial biology and highlight microglia as possible targets for therapeutic interventions in neurodegenerative disease. Expected final online publication date for the Annual Review of Genetics, Volume 53 is November 23, 2019. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8035,"journal":{"name":"Annual review of genetics","volume":" ","pages":""},"PeriodicalIF":11.1,"publicationDate":"2019-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1146/annurev-genet-112618-043515","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43015315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}