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Sex Chromosome-Wide Transcriptional Suppression And Compensatory Cis-Regulatory Evolution Mediate Gene Expression In The Drosophila Male Germline, Emily L. Landeen, Christina A. Muirhead, Lori Wright, Colin D. Meiklejohn, Daven C. Presgraves Jul 2016

Sex Chromosome-Wide Transcriptional Suppression And Compensatory Cis-Regulatory Evolution Mediate Gene Expression In The Drosophila Male Germline, Emily L. Landeen, Christina A. Muirhead, Lori Wright, Colin D. Meiklejohn, Daven C. Presgraves

School of Biological Sciences: Faculty Publications

The evolution of heteromorphic sex chromosomes has repeatedly resulted in the evolution of sex chromosome-specific forms of regulation, including sex chromosome dosage compensation in the soma and meiotic sex chromosome inactivation in the germline. In the male germline of Drosophila melanogaster, a novel but poorly understood form of sex chromosome-specific transcriptional regulation occurs that is distinct from canonical sex chromosome dosage compensation or meiotic inactivation. Previous work shows that expression of reporter genes driven by testis-specific promoters is considerably lower—approximately 3-fold or more—for transgenes inserted into X chromosome versus autosome locations. Here we characterize this transcriptional suppression of X-linked …


The Maintenance Of Phenotypic Divergence Through Sexual Selection: An Experimental Study In Barn Swallows Hirundo Rustica, Rebecca Safran, Yoni Vortman, Brittany R. Jenkins, Joanna K. Hubbard, Matt Wilkins, Rachel J. Bradley, Arnon Lotem Jul 2016

The Maintenance Of Phenotypic Divergence Through Sexual Selection: An Experimental Study In Barn Swallows Hirundo Rustica, Rebecca Safran, Yoni Vortman, Brittany R. Jenkins, Joanna K. Hubbard, Matt Wilkins, Rachel J. Bradley, Arnon Lotem

School of Biological Sciences: Faculty Publications

Previous studies have shown that sexual signals can rapidly diverge among closely related species. However, we lack experimental studies to demonstrate that differences in trait-associated reproductive performance maintain sexual trait differences between closely related populations, in support for a role of sexual selection in speciation. Populations of Northern Hemisphere distributed barn swallows Hirundo rustica are closely related, yet differ in two plumage-based traits: ventral color and length of the outermost tail feathers (streamers). Here we provide experimental evidence that manipulations of these traits result in different reproductive consequences in two subspecies of barn swallow: (H. r. erythrogaster in North …


Corrigendum: The Arabidopsis Homologs Of Trithorax (Atx1) And Enhancer Of Zeste (Clf) Establish ‘Bivalent Chromatin Marks’ At The Silent Agamous Locus, Abdelaty Saleh, Ayed Al-Abdallat, Ivan Ndamukong, Raul Alvarez-Venegas, Zoya Avramova Jan 2016

Corrigendum: The Arabidopsis Homologs Of Trithorax (Atx1) And Enhancer Of Zeste (Clf) Establish ‘Bivalent Chromatin Marks’ At The Silent Agamous Locus, Abdelaty Saleh, Ayed Al-Abdallat, Ivan Ndamukong, Raul Alvarez-Venegas, Zoya Avramova

School of Biological Sciences: Faculty Publications

The authors wish to draw the attention to two irregularities in Figures 2a and 4. Both concern errors in duplicating images of "empty" lanes illustrating absence of DNA bands. We regret these omissions and apologize to readers for the inconvenience caused. The results and conclusions remain valid.


Aba Signaling Is Necessary But Not Sufficient For Rd29b Transcriptional Memory During Successive Dehydration Stresses In Arabidopsis Thaliana, Laetitia Virlouvet, Yong Ding, Hiroaki Fujii, Zoya Avramova, Michael Fromm Jan 2014

Aba Signaling Is Necessary But Not Sufficient For Rd29b Transcriptional Memory During Successive Dehydration Stresses In Arabidopsis Thaliana, Laetitia Virlouvet, Yong Ding, Hiroaki Fujii, Zoya Avramova, Michael Fromm

School of Biological Sciences: Faculty Publications

Plants subjected to a prior dehydration stress were seen to have altered transcriptional responses during a subsequent dehydration stress for up to 5 days after the initial stress. The abscisic acid (ABA) inducible RD29B gene of Arabidopsis thaliana was strongly induced after the first stress and displayed transcriptional memory with transcript levels nine-fold higher during the second dehydration stress. These increased transcript levels were due to an increased rate of transcription and are associated with an altered chromatin template during the recovery interval between the dehydration stresses. Here we use a combination of promoter deletion/substitutions, mutants in the trans-acting …


Atx1/Atcompass And The H3k4me3 Marks: How Do They Activate Arabidopsis Genes?, Michael E. Fromm, Zoya Avramova Jan 2014

Atx1/Atcompass And The H3k4me3 Marks: How Do They Activate Arabidopsis Genes?, Michael E. Fromm, Zoya Avramova

School of Biological Sciences: Faculty Publications

Despite the proven correlation between gene transcriptional activity and the levels of tri-methyl marks on histone 3 lysine4 (H3K4me3) of their nucleosomes, whether H3K4me3 contributes to, or “registers,” activated transcription is still controversial. Other questions of broad relevance are whether histone-modifying proteins are involved in the recruitment of Pol II and the general transcription machinery and whether they have roles other than their enzyme activities. We address these questions as well as the roles of the ARABIDOPSIS HOMOLOG OF TRITHORAX1 (ATX1), of the COMPASS-related (AtCOMPASS) protein complex, and of their product, H3K4me3, at ATX1-dependent genes. We suggest that the ambiguity …


H3k27me3 And H3k4me3 Chromatin Environment At Super-Induced Dehydration Stress Memory Genes Of Arabidopsis Thaliana, Ning Liu, Zoya Avramova, Michael Fromm Jan 2014

H3k27me3 And H3k4me3 Chromatin Environment At Super-Induced Dehydration Stress Memory Genes Of Arabidopsis Thaliana, Ning Liu, Zoya Avramova, Michael Fromm

School of Biological Sciences: Faculty Publications

Pre-exposure to a stress may alter the plant’s cellular, biochemical, and/or transcriptional responses during future encounters as a “memory” from the previous stress. Genes increasing transcription in response to a first dehydration stress, but producing much higher transcript levels in a subsequent stress, represent the super-induced “transcription memory” genes in Arabidopsis thaliana. The chromatin environment (histone H3 tri-methylations of Lys 4 and Lys 27, H3K4me3, and H3K27me3) studied at five dehydration stress memory genes revealed existence of distinct memory-response subclasses that responded differently to CLF deficiency and displayed different transcriptional activities during the watered recovery periods. Among the most …


Divergent Functions Of The Myotubularin (Mtm) Homologs Atmtm1 And Atmtm2 In Arabidopsis Thaliana: Evolution Of The Plant Mtm Family, Yong Ding, Ivan Ndamukong, Yang Zhao, Yuannan Xia, Jean-Jack Riethoven, David R. Jones, Nullin Divecha, Zoya Avramova Jan 2012

Divergent Functions Of The Myotubularin (Mtm) Homologs Atmtm1 And Atmtm2 In Arabidopsis Thaliana: Evolution Of The Plant Mtm Family, Yong Ding, Ivan Ndamukong, Yang Zhao, Yuannan Xia, Jean-Jack Riethoven, David R. Jones, Nullin Divecha, Zoya Avramova

School of Biological Sciences: Faculty Publications

Myotubularin and myotubularin-related proteins are evolutionarily conserved in eukaryotes. Defects in their function result in muscular dystrophy, neuronal diseases, and leukemia in humans. In contrast to the animal lineage, where genes encoding both active and inactive myotubularins (phosphoinositide 3-phosphatases) have appeared and proliferated in the basal metazoan group, myotubularin genes are not found in the unicellular relatives of green plants. However, they are present in land plants encoding proteins highly similar to the active metazoan enzymes. Despite their remarkable structural conservation, plant and animal myotubularins have significantly diverged in their functions. While loss of myotubularin function causes severe disease phenotypes …


The Arabidopsis Trithorax-Like Factor Atx1 Functions In Dehydration Stress Responses Via Aba-Dependent And Aba-Independent Pathways, Yong Ding, Zoya Avramova, Michael Fromm Jan 2011

The Arabidopsis Trithorax-Like Factor Atx1 Functions In Dehydration Stress Responses Via Aba-Dependent And Aba-Independent Pathways, Yong Ding, Zoya Avramova, Michael Fromm

School of Biological Sciences: Faculty Publications

Emerging evidence suggests that the molecular mechanisms driving the responses of plants to environmental stresses are associated with specific chromatin modifications. Here, we demonstrate that the Arabidopsis trithorax-like factor ATX1, which trimethylates histone H3 at lysine 4 (H3K4me3), is involved in dehydration stress signaling in both abscisic acid (ABA)-dependent and ABA-independent pathways. The loss of function of ATX1 results in decreased germination rates, larger stomatal apertures, more rapid transpiration and decreased tolerance to dehydration stress in atx1 plants. This deficiency is caused in part by reduced ABA biosynthesis in atx1 plants resulting from decreased transcript levels from NCED3, which …


Copper Tolerance Of Saccharomyces Cerevisiae Nonsense-Mediated Mrna Decay Mutants, Rafael Deliz-Aguirre, Audrey L. Atkin, Bessie W. Kebaara Jan 2011

Copper Tolerance Of Saccharomyces Cerevisiae Nonsense-Mediated Mrna Decay Mutants, Rafael Deliz-Aguirre, Audrey L. Atkin, Bessie W. Kebaara

School of Biological Sciences: Faculty Publications

The eukaryotic nonsense-mediated mRNA (NMD) is a specialized pathway that leads to the recognition and rapid degradation of mRNAs with premature termination codons, and importantly some natural mRNAs as well. Natural mRNAs with atypically long 3′-untranslated regions (UTRs) are degraded by NMD in Saccharomyces cerevisiae. A number of S. cerevisiae mRNAs undergo alternative 3′-end processing producing mRNA isoforms that differ in their 3′-UTR lengths. Some of these alternatively 3′-end processed mRNA isoforms have atypically long 3′-UTRs and would be likely targets for NMD-mediated degradation. Here, we investigated the role NMD plays in the regulation of expression of CTR2, …


Wnt And Egf Pathways Act Together To Induce C. Elegans Male Hook Development, Hui Yu, Adeline Seah, Michael A. Herman, Edwin L. Ferguson, H. Robert Horvitz, Paul W. Sternberg Mar 2009

Wnt And Egf Pathways Act Together To Induce C. Elegans Male Hook Development, Hui Yu, Adeline Seah, Michael A. Herman, Edwin L. Ferguson, H. Robert Horvitz, Paul W. Sternberg

School of Biological Sciences: Faculty Publications

Comparative studies of vulva development between Caenorhabditis elegans and other nematode species have provided some insight into the evolution of patterning networks. However, molecular genetic details are available only in C. elegans and Pristionchus pacificus. To extend our knowledge on the evolution of patterning networks, we studied the C. elegans male hook competence group (HCG), an equivalence group that has similar developmental origins to the vulval precursor cells (VPCs), which generate the vulva in the hermaphrodite. Similar to VPC fate specification, each HCG cell adopts one of three fates (1°, 2°, 3°), and 2° HCG fate specification …


Ecological Genomics: Understanding Gene And Genome Function In The Natural Environment, M. C. Ungerer, L. C. Johnson, M. A. Herman Jan 2008

Ecological Genomics: Understanding Gene And Genome Function In The Natural Environment, M. C. Ungerer, L. C. Johnson, M. A. Herman

School of Biological Sciences: Faculty Publications

The field of ecological genomics seeks to understand the genetic mechanisms underlying responses of organisms to their natural environments. This is being achieved through the application of functional genomic approaches to identify and characterize genes with ecological and evolutionary relevance. By its very nature, ecological genomics is an interdisciplinary field. In this review, we consider the significance of this new area of study from both an ecological and genomic perspective using examples from the recent literature. We submit that by considering more fully an ecological context, researchers may gain additional insights into the underlying genetic basis of ecologically relevant phenotypic …


Asymmetric Localizations Of Lin-17/Fz And Mig-5/Dsh Are Involved In The Asymmetric B Cell Division In C. Elegans, Mingfu Wu, Michael A. Herman Jan 2007

Asymmetric Localizations Of Lin-17/Fz And Mig-5/Dsh Are Involved In The Asymmetric B Cell Division In C. Elegans, Mingfu Wu, Michael A. Herman

School of Biological Sciences: Faculty Publications

LIN-44/Wnt and LIN-17/Frizzled (Fz) function in a planar cell polarity (PCP)-like pathway to regulate the asymmetric B cell division in Caenorhabditis elegans. We observed asymmetric localization of LIN-17/Frizzled (Fz) and MIG-5/Disheveled (Dsh) during the B cell division. LIN-17∷GFP was asymmetrically localized within the B cell prior to and after the B cell division and correlated with B cell polarity. Asymmetric localization of LIN-17∷GFP was dependent upon LIN-44/Wnt and MIG-5/Dsh function. The LIN-17 transmembrane domain and a portion of the cysteine-rich domain (CRD) were required for LIN-17 function and asymmetric distribution to the B cell daughters, while the conserved KTXXXW …


Microarray Challenges In Ecology, Jan E. Kammenga, Michael A. Herman, N. Joop Ouborg, Loretta Johnson, Rainer Bretling Jan 2007

Microarray Challenges In Ecology, Jan E. Kammenga, Michael A. Herman, N. Joop Ouborg, Loretta Johnson, Rainer Bretling

School of Biological Sciences: Faculty Publications

Microarrays are used to measure simultaneously the amount of mRNAs transcribed from many genes. They were originally designed for gene expression profiling in relatively simple biological systems, such as cell lines and model systems under constant laboratory conditions. This poses a challenge to ecologists who increasingly want to use microarrays to unravel the genetic mechanisms underlying complex interactions among organisms and between organisms and their environment. Here, we discuss typical experimental and statistical problems that arise when analyzing genome-wide expression profiles in an ecological context. We show that experimental design and environmental confounders greatly influence the identification of candidate genes …


The Arabidopsis Homologs Of Trithorax (Atx1) And Enhancer Of Zeste (Clf) Establish ‘Bivalent Chromatin Marks’ At The Silent Agamous Locus, Abdelaty Saleh, Ayed Al-Abdallat, Ivan Ndamukong, Raul Alvarez-Venegas, Zoya Avramova Jan 2007

The Arabidopsis Homologs Of Trithorax (Atx1) And Enhancer Of Zeste (Clf) Establish ‘Bivalent Chromatin Marks’ At The Silent Agamous Locus, Abdelaty Saleh, Ayed Al-Abdallat, Ivan Ndamukong, Raul Alvarez-Venegas, Zoya Avramova

School of Biological Sciences: Faculty Publications

Tightly balanced antagonism between the Polycomb group (PcG) and the Trithorax group (TrxG) complexes maintain Hox expression patterns in Drosophila and murine model systems. Factors belonging to the PcG/TrxG complexes control various processes in plants as well but whether they participate in mechanisms that antagonize, balance or maintain each other’s effects at a particular gene locus is unknown. CURLY LEAF (CLF), an Arabidopsis homolog of enhancer of zeste (EZ) and the ARABIDOPSIS HOMOLOG OF TRITHORAX (ATX1) control the expression of the flower homeotic gene AGAMOUS (AG). Disrupted ATX1 or CLF function results in misexpression of AG, recognizable …


Upf1p, A Highly Conserved Protein Required For Nonsense-Mediated Mrna Decay, Interacts With The Nuclear Pore Proteins Nup100p And Nup116p, Tara Nazarenus, Rebecca Cedarberg, Ryan Bell, Joseph Cheatle, Amanda Forch, Alexis Haifley, Ann Hou, Bessie Wanja Kebaara, Christina Shields, Kate Stoysich, Rachel Taylor, Audrey L. Atkin Jan 2005

Upf1p, A Highly Conserved Protein Required For Nonsense-Mediated Mrna Decay, Interacts With The Nuclear Pore Proteins Nup100p And Nup116p, Tara Nazarenus, Rebecca Cedarberg, Ryan Bell, Joseph Cheatle, Amanda Forch, Alexis Haifley, Ann Hou, Bessie Wanja Kebaara, Christina Shields, Kate Stoysich, Rachel Taylor, Audrey L. Atkin

School of Biological Sciences: Faculty Publications

Saccharomyces cerevisiae Upf1p is a 971-amino-acid protein that is required for the nonsense-mediated mRNA decay (NMD) pathway, a pathway that degrades mRNAs with premature translational termination codons. We have identified a two-hybrid interaction between Upf1p and the nuclear pore (Nup) proteins, Nup100p and Nup116p. Both nucleoporins predominantly localize to the cytoplasmic side of the nuclear pore and participate in mRNA transport. The two-hybrid interaction between Upf1p and the nuclear pore proteins, Nup100p and Nup116p, is dependent on the presence of the C-terminal 158 amino acids of Upf1p. Nup100p and Nup116p can be coimmunoprecipitated from whole-cell extracts with Upf1p, confirming in …


Can Genetically Engineered Crops Become Weeds?, Kathleen H. Keeler Nov 1989

Can Genetically Engineered Crops Become Weeds?, Kathleen H. Keeler

School of Biological Sciences: Faculty Publications

There are significant differences if the distribution of weedy characteristics among weeds, normal plants, and crops. The world’s most serious weeds possess on the average 10 or 11 of these characters, a random collection of British plants have an average seven of the traits, and crop plants only five. For the average crop to become as “weedy” as the average weed, it would need to acquire five weedy traits. Even using the unlikely assumption that those traits are single loci in which a dominant mutation would provide the weedy character, this would require the simultaneous acquisition of five gene substitutions. …