202 research outputs found

    Toward the Prevention of Risky Sexual Behavior Among Latina Youth

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    Sexual risk-taking among Latina youth has been noted as a critical health concern within the United States. In this chapter. the importance of prevention of risky sexual behavior among Latina youth will be discussed. Current prevalence rates and consequences associated with sexual behavior among Latino/as will be reviewed. along with factors that are relevant to understanding the prevention of sexual activity. Finally. programs that have been developed to prevent risky sexual behavior among Latinas will be reviewed and suggestions for prevention efforts will be presented

    Zim1, a maternally expressed mouse Kruppel-type zinc-finger gene located in proximal chromosome 7

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    In analysis of a conserved region of proximal mouse chromosome 7 and human chromosome 19q, we have isolated a novel mouse gene, Zim1 (imprinted zinc-finger gene 1), encoding a typical Kruppel-type (C2H2) zinc-finger protein, located within 30 kb of a known imprinted gene, Peg3 (paternally expressed gene 3). Our studies demonstrate that Zim1 is also imprinted; the gene is expressed mainly from the maternal allele and at high levels only during embryonic and neonatal stages. In contrast to most tissues, Zim1 is expressed biallelically in neonatal and adult brain with slightly more input from the maternal allele. Zim1 produces multiple transcripts that range in size from 7.5 to 15 kb. The 7.5 kb transcript is expressed at highest levels and appears to be embryo specific. Whole mount in situ hybridization analysis indicates that Zim1 is expressed at significant levels in the apical ectodermal ridge of the limb buds during embryogenesis, suggesting a potential role of Zim1 in limb formation. We have identified the potential human ortholog of Zim1 near PEG3 in a conserved, gene-rich region of human chromosome 19q13.4. The close juxtaposition of reciprocally imprinted genes has also been seen in other imprinted regions, such as human 11p15.5/Mmu7 (H19/Igf2) and suggests that the two genes may be co-regulated. These and other data suggest the presence of an unexplored, conserved imprinted domain in human chromosome 19q13.4 and proximal Mmu7

    ZIPK: A Unique Case of Murine-Specific Divergence of a Conserved Vertebrate Gene

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    Zipper interacting protein kinase (ZIPK, also known as death-associated protein kinase 3 [DAPK3]) is a Ser/Thr kinase that functions in programmed cell death. Since its identification eight years ago, contradictory findings regarding its intracellular localization and molecular mode of action have been reported, which may be attributed to unpredicted differences among the human and rodent orthologs. By aligning the sequences of all available ZIPK orthologs, from fish to human, we discovered that rat and mouse sequences are more diverged from the human ortholog relative to other, more distant, vertebrates. To test experimentally the outcome of this sequence divergence, we compared rat ZIPK to human ZIPK in the same cellular settings. We found that while ectopically expressed human ZIPK localized to the cytoplasm and induced membrane blebbing, rat ZIPK localized exclusively within nuclei, mainly to promyelocytic leukemia oncogenic bodies, and induced significantly lower levels of membrane blebbing. Among the unique murine (rat and mouse) sequence features, we found that a highly conserved phosphorylation site, previously shown to have an effect on the cellular localization of human ZIPK, is absent in murines but not in earlier diverging organisms. Recreating this phosphorylation site in rat ZIPK led to a significant reduction in its promyelocytic leukemia oncogenic body localization, yet did not confer full cytoplasmic localization. Additionally, we found that while rat ZIPK interacts with PAR-4 (also known as PAWR) very efficiently, human ZIPK fails to do so. This interaction has clear functional implications, as coexpression of PAR-4 with rat ZIPK caused nuclear to cytoplasm translocation and induced strong membrane blebbing, thus providing the murine protein a possible adaptive mechanism to compensate for its sequence divergence. We have also cloned zebrafish ZIPK and found that, like the human and unlike the murine orthologs, it localizes to the cytoplasm, and fails to bind the highly conserved PAR-4 protein. This further supports the hypothesis that murine ZIPK underwent specific divergence from a conserved consensus. In conclusion, we present a case of species-specific divergence occurring in a specific branch of the evolutionary tree, accompanied by the acquisition of a unique protein–protein interaction that enables conservation of cellular function

    Methylation-sensitive binding of transcription factor YY1 to an insulator sequence within the paternally expressed imprinted gene, Peg3

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    The 5�-ends of two paternally expressed mouse genes, Peg3 and Usp29, are jointly associated with a CpG island that exhibits allele-specific methylation. Sequence comparison of the regions derived from human, mouse and cow revealed the presence of two evolutionarily conserved sequence motifs including one that is repeated multiple times within the first intron of Peg3 in all three mammals. DNA mobility shift and chromatin immunoprecipitation (ChlP) assays clearly demonstrated that this motif is an in vivo binding site for the Gli-type transcription factor YY1. The YY1-binding site contains one CpG dinucleotide, and methylation of this CpG site abolishes the binding activity of YY1 in vitro. The Peg3 YY1-binding sites are methylated only on the maternal chromosome in vivo, and ChlP assays confirmed that YY1 binds specifically to the paternal allele of the gene. Promoter, enhancer and insulator assays with deletion constructs of sequence surrounding the YY1-binding sites indicate that the region functions as a methylation-sensitive insulator that may influence the imprinted expression of Peg3 and neighboring genes. The current study is the first report demonstrating the involvement of YY1 in methylation-sensitive insulator activity and suggests a potential role of this highly conserved protein in mammalian genomic imprinting. © Oxford University Press 2001

    Rapid evolution of a recently retroposed transcription factor YY2 in mammalian genomes

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    YY2 was originally identified due to its unusual similarity to the evolutionarily well-conserved zinc finger gene YY1. In this study, we have determined the evolutionary origin and conservation of YY2 using comparative genomic approaches. Our results indicate that YY2 is a retroposed copy of YY1 that has been inserted into another gene locus named Mbtps2 (membrane-bound transcription factor protease site 2). This retroposition is estimated to have occurred after the divergence of placental mammals from other vertebrates based on the detection of YY2 only in the placental mammals. The N- and C-terminal regions of YY2 have evolved under different selection pressures. The N-terminal region has evolved at a very fast pace with very limited functional constraints, whereas the DNA-binding, C-terminal region still maintains a sequence structure very similar to that of YY1 and is also well conserved among placental mammals. In situ hybridizations using different adult mouse tissues indicate that mouse YY2 is expressed at relatively low levels in Purkinje and granular cells of cerebellum and in neuronal cells of cerebrum, but at very high levels in testis. The expression levels of YY2 are much lower than those of YY1, but the overall spatial expression patterns are similar to those of Mbtps2, suggesting a possible shared transcriptional control between YY2 and Mbtps2. Taken together, the formation and evolution of YY2 represent a very unusual case where a transcription factor was first retroposed into another gene locus encoding a protease and survived with different selection schemes and expression patterns. © 2005 Elsevier Inc. All rights reserved

    Thick Slice Clarity for Localization of Novel Neuroactive Target Gene Products

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    This poster describes the Thick Slice CLARITY technique, an alternative to the whole tissue or whole body clarity technique. The CLARITY technique is a tissue clearing method allowing for both structural and molecular analysis of a tissue sample, but the method applied to whole tissue or body is very expensive and time consuming. Thick Slice CLARITY applies the same principles but to a 200 micrometer slice of brain tissue. This method, used in conjunction wit standard fluorescent staining methods and imaging via confocal microscopy, has allowed for the colocalization of GPR3 with neurons in the mouse striatum

    Genomic organization and imprinting of the Peg3 domain in bovine

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    AbstractUsing multiple mammalian genomic sequences, we have analyzed the evolution and imprinting of several genes located in the Peg3 domain, including Mim1 (approved name, Mimt1), Usp29, Zim3, and Zfp264. A series of comparative analyses shows that the overall genomic structure of this 500-kb imprinted domain has been well maintained throughout mammalian evolution but that several lineage-specific changes have also occurred in each species. In the bovine domain, Usp29 has lost its protein-coding capability, Zim3 has been duplicated, and the expression of Zfp264 has become biallelic in brain and testis, which differs from paternal expression of mouse Zfp264 in brain. In contrast, the two transcript genes of cow, Mim1 and Usp29, both lacking protein-coding capability, are still expressed mainly from the paternal allele, indicating the imprinting of these two genes in cow. The imprinting of Mim1 and Usp29 along with Peg3 is the most evolutionarily selected feature in this imprinted domain, suggesting significant function of these three genes, either as protein-coding or as untranslated transcript genes

    The Alternative Choice of Constitutive Exons throughout Evolution

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    Alternative cassette exons are known to originate from two processes exonization of intronic sequences and exon shuffling. Herein, we suggest an additional mechanism by which constitutively spliced exons become alternative cassette exons during evolution. We compiled a dataset of orthologous exons from human and mouse that are constitutively spliced in one species but alternatively spliced in the other. Examination of these exons suggests that the common ancestors were constitutively spliced. We show that relaxation of the 59 splice site during evolution is one of the molecular mechanisms by which exons shift from constitutive to alternative splicing. This shift is associated with the fixation of exonic splicing regulatory sequences (ESRs) that are essential for exon definition and control the inclusion level only after the transition to alternative splicing. The effect of each ESR on splicing and the combinatorial effects between two ESRs are conserved from fish to human. Our results uncover an evolutionary pathway that increases transcriptome diversity by shifting exons from constitutive to alternative splicin

    YY1 as a controlling factor for the Peg3 and Gnas imprinted domains

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    AbstractImprinting control regions (ICRs) often harbor tandem arrays of transcription factor binding sites, as demonstrated by the identification of multiple YY1 binding sites within the ICRs of Peg3, Nespas, and Xist/Tsix domains. In the current study, we have sought to characterize possible roles for YY1 in transcriptional control and epigenetic modification of these imprinted domains. RNA interference-based knockdown experiments in Neuro2A cells resulted in overall transcriptional up-regulation of most of the imprinted genes within the Peg3 domain and also, concomitantly, caused significant loss in the DNA methylation of the Peg3 differentially methylated region. A similar overall and coordinated expression change was also observed for the imprinted genes of the Gnas domain: up-regulation of Nespas and down-regulation of Nesp and Gnasxl. YY1 knockdown also resulted in changes in the expression levels of Xist and Snrpn. These results support the idea that YY1 plays a major role, as a trans factor, in the control of these imprinted domains
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