Karyotype of Araucaria angustifolia and the decondensation/activation mode of its nucleolus organiser region

2007 ◽  
Vol 55 (2) ◽  
pp. 165 ◽  
Author(s):  
Manoela Miranda ◽  
Cícero Carlos de Souza Almeida ◽  
Marcelo Guerra
Keyword(s):  
Transcriptional Activation ◽  
Chromosome Pair ◽  
Transcriptional Control ◽  
Rrna Genes ◽  
Araucaria Angustifolia ◽  
Organiser Region ◽  
C Banding ◽  
Diploid Complement ◽  
Nucleolus Organiser ◽  
Nucleolus Organiser Region

The chromosomes of the gymnosperm Araucaria angustifolia (Bertol.) Kuntze were analysed with the fluorochromes chromomycin A3 (CMA) and 4′,6-diamidino-2-phenylindole (DAPI) and with C-banding. This species contains a diploid complement made of 26 chromosomes, with 18 larger metacentric, four smaller metacentric and four submetacentric chromosomes. The only CMA+/DAPI– region observed corresponded to the nucleolus organiser region (NOR) localised at the proximal portion of a large metacentric chromosome pair. C-banding marked the NOR as well as a terminal region of another chromosome pair. In addition, small C-bands were occasionally seen interspersed in many chromosomes. The NOR appeared to condense at approximately the same rate as the rest of the chromosome from prophase throughout metaphase. In interphase nuclei, NOR decondensation and activation was characterised by the formation of CMA+ blocks that resembled a string of beads inside the nucleolus. The number and size of beads was inversely proportional to the size of the nucleolus, suggesting that transcriptional activation of the nucleolar cistrons starts simultaneously at several points of the NOR. The mode of NOR activation in A. angustifolia differs from that observed in most species, providing a unique opportunity to study activation and transcriptional control of rRNA genes.

A supernumerary chromosome segment in Locusta migratoria

Genome ◽  
1993 ◽  
Vol 36 (5) ◽  
pp. 919-923 ◽  
Author(s):  
M. C. Pardo ◽  
E. Viseras ◽  
J. Cabrero ◽  
J. P. M. Camacho
Keyword(s):  
Dna Sequences ◽  
Locusta Migratoria ◽  
Supernumerary Chromosome ◽  
Rrna Genes ◽  
Single Female ◽  
Nucleolar Organizing Regions ◽  
Extra Segment ◽  
Accumulation Mechanism ◽  
Nucleolus Organiser ◽  
Nucleolus Organiser Region

A single female of Locusta migratoria was found to be heterozygous for a supernumerary heterochromatic segment distally located on the M6 autosome close to its nucleolus organiser region (NOR). Reactions to several chromosome banding techniques revealed its heterochromatic nature and its composition of GC-rich DNA sequences and likewise the NORs in this species. This suggests an origin for the extra segment by amplification of GC-rich DNA sequences contained in the distal NOR of the M6 chromosome, which is reinforced by the observation that the NOR of segmented M6 chromosomes produced the larger nucleolus in embryo prophase cells, such as would be expected from the presence of rRNA genes in the extra segment. No accumulation mechanism was detected in this female after analyzing the 213 embryo offspring produced, but an increase in the number of nucleoli per interphase nucleus was noted in heterozygous embryos in respect to standard homozygous ones.Key words: Locusta migratoria, supernumerary segments, nucleolar organizing regions, heterochromatin.

scholarly journals Cytogenetical analyses in three fish species of the genus Pimelodus(Siluriformes: Pimelodidae) from rio São Francisco: considerations about the karyotypical evolution in the genus

2005 ◽  
Vol 3 (2) ◽  
pp. 285-290 ◽  
Author(s):  
Caroline Garcia ◽  
Orlando Moreira Filho
Keyword(s):  
Chromosome Pair ◽  
Chromosomal Rearrangements ◽  
Nucleolar Organizer ◽  
Differential Staining ◽  
Nucleolar Organizer Regions ◽  
C Banding ◽  
Heteromorphic Sex Chromosomes ◽  
Chromosomal Markers ◽  
Staining Techniques ◽  
Species Specific

Karyotypes and other chromosomal markers were investigated in three species of the catfish genus Pimelodus, namely P. fur, P. maculatus and Pimelodus sp., from municipality of Três Marias, Minas Gerais, Brazil, using differential staining techniques (C-banding, Silver nitrate and CMA3 staining). The diploid chromosome number was 2n = 56 in P. maculatus and Pimelodus sp., while in P. fur 2n = 54. The karyotype of P. fur consisted in 32M + 8SM + 6ST + 8A with fundamental number (NF) of 100, that of P. maculatus 32M + 12SM + 12A with NF = 112, and that of Pimelodus sp. had 32M + 12Sm + 6ST + 6A with NF = 106.The nucleolar organizer regions (NORs) in all three species were invariably detected in telomeres of longer arm of the 20th chromosome pair. These sites were also positive after CMA3 and C-banding. No heteromorphic sex chromosomes were detected and C-banding pattern was species specific. Inferences about the karyotype differentiation in Pimelodus and putative chromosomal rearrangements are hypohesized.

scholarly journals Elevated cJUN expression and an ATF/CRE site within the ATF3 promoter contribute to activation of ATF3 transcription by the amino acid response

2013 ◽  
Vol 45 (4) ◽  
pp. 127-137 ◽  
Author(s):  
Lingchen Fu ◽  
Michael S. Kilberg
Keyword(s):  
Amino Acid ◽  
Transcriptional Activation ◽  
Translational Control ◽  
Mammalian Cells ◽  
Transcriptional Control ◽  
Present Report ◽  
Binding Activity ◽  
Maximal Response ◽  
Protein Levels ◽  
Amino Acid Response

Mammalian cells respond to amino acid deprivation through multiple signaling pathways referred to as the amino acid response (AAR). Transcription factors mediate the AAR after their activation by several mechanisms; examples include translational control (activating transcription factor 4, ATF4), phosphorylation (p-cJUN), and transcriptional control (ATF3). ATF4 induces ATF3 transcription through a promoter-localized C/EBP-ATF response element (CARE). The present report characterizes an ATF/CRE site upstream of the CARE that also contributes to AAR-induced ATF3 transcription. ATF4 binds to the ATF/CRE and CARE sequences and both are required for a maximal response to ATF4 induction. ATF3, which antagonizes ATF4 and represses its own gene, also exhibited binding activity to the ATF/CRE and CARE sequences. The AAR resulted in elevated total cJUN and p-cJUN protein levels and both forms exhibited binding activity to the ATF/CRE and CARE ATF3 sequences. Knockdown of AAR-enhanced cJUN expression blocked induction of the ATF3 gene and mutation of either the ATF/CRE or the CARE site prevented the cJUN-dependent increase in ATF3-driven luciferase activity. The results indicate that both increased cJUN and the cis-acting ATF/CRE sequence within the ATF3 promoter contribute to the transcriptional activation of the gene during the AAR.

Functional domains of a positive regulatory protein, PHO4, for transcriptional control of the phosphatase regulon in Saccharomyces cerevisiae

1990 ◽  
Vol 10 (5) ◽  
pp. 2224-2236
Author(s):  
N Ogawa ◽  
Y Oshima
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Transcriptional Activation ◽  
Transcriptional Control ◽  
Regulatory Protein ◽  
Mitochondrial Protein ◽  
Functional Domains ◽  
Regulatory Factor ◽  
Coding Region ◽  
Protein Determination ◽  
Transcriptional Activation Domain

The PHO4 gene encodes a positive regulatory factor involved in regulating transcription of various genes in the phosphatase regulon of Saccharomyces cerevisiae. Besides its own coding region, the 1.8-kilobase PHO4 transcript contains a coding region for a mitochondrial protein which does not appear to be translated. Four functional domains were found in the PHO4 protein, which consists of 312 amino acid (aa) residues as deduced from the open reading frame of PHO4. A gel retardation assay with beta-galactosidase::PHO4 fused protein revealed that the 85-aa C terminus is the domain responsible for binding to the promoter DNA of PHO5, a gene under the control of PHO4. This region has similarities with the amphipathic helix-loop-helix motif of c-myc protein. Determination of the nucleotide sequences of four PHO4c mutant alleles and insertion and deletion analyses of PHO4 DNA indicated that a region from aa 163 to 202 is involved in interaction with a negative regulatory factor PHO80. Complementation of a pho4 null allele with the modified PHO4 DNAs suggested that the N-terminal region (1 to 109 aa), which is rich in acidic aa, is the transcriptional activation domain. The deleterious effects of various PHO4 mutations on the constitutive transcription of PHO5 in PHO4c mutant cells suggested that the region from aa 203 to 227 is involved in oligomerization of the PHO4 protein.

scholarly journals Competence Modulation by the NADH Oxidase ofStreptococcus pneumoniae Involves Signal Transduction

2001 ◽  
Vol 183 (2) ◽  
pp. 768-772 ◽  
Author(s):  
José R. Echenique ◽  
Marie C. Trombe
Keyword(s):  
Signal Transduction ◽  
Transcriptional Activation ◽  
Transcriptional Control ◽  
Nadh Oxidase ◽  
Response Regulator ◽  
Transcriptional Analysis ◽  
Genetic Dissection ◽  
Oxygen Signaling ◽  
Two Component Signal Transduction ◽  
Signal Transduction Systems

ABSTRACT Oxygen controls competence development in Streptococcus pneumoniae. Oxygen signaling involves the two-component signal transduction systems CiaRH and ComDE and the competence-stimulating peptide encoded by comC and processed by ComAB. We found that NADH oxidase (Nox) was required for optimal competence. Transcriptional analysis and genetic dissection showed that Nox was involved in post-transcriptional activation of the response regulator ComE and in the transcriptional control of ciaRH andcomCDE. Thus, in S. pneumoniae, Nox, with O2 as its secondary substrate, is part of the O2-signaling pathway.

scholarly journals Transcriptional Activation of the Telomerase hTERT Gene by Human Papillomavirus Type 16 E6 Oncoprotein

2001 ◽  
Vol 75 (9) ◽  
pp. 4467-4472 ◽  
Author(s):  
Tim Veldman ◽  
Izumi Horikawa ◽  
J. Carl Barrett ◽  
Richard Schlegel
Keyword(s):  
Human Papillomavirus ◽  
Transcriptional Activation ◽  
Transcriptional Control ◽  
Regulatory Region ◽  
Rnase Protection ◽  
Hpv 16 ◽  
Htert Gene ◽  
Human Papillomavirus Type 16 ◽  
E6 Gene

ABSTRACT The E6 and E7 oncogenes of human papillomavirus type 16 (HPV-16) are sufficient for the immortalization of human genital keratinocytes in vitro. The products of these viral genes associate with p53 and pRb tumor suppressor proteins, respectively, and interfere with their normal growth-regulatory functions. The HPV-16 E6 protein has also been shown to increase the telomerase enzyme activity in primary epithelial cells by an unknown mechanism. We report here that a study using reverse transcription-PCR and RNase protection assays in transduced primary human foreskin keratinocytes (HFKs) shows that the E6 gene (but not the E7 gene) increases telomerase hTERT gene transcription coordinately with E6-induced telomerase activity. In these same cells, the E6 gene induces a 6.5-fold increase in the activity of a 1,165-bp 5′ promoter/regulatory region of the hTERT gene, and this induction is attributable to a minimal 251-bp sequence (−211 to +40). Furthermore, there is a 35-bp region (+5 to +40) within this minimal E6-responsive promoter that is responsible for 60% of E6 activity. Although the minimal hTERT promoter contains Myc-responsive E-box elements and recent studies have suggested a role for Myc protein in hTERT transcriptional control, we found no alterations in the abundance of either c-Myc or c-Mad in E6-transduced HFKs, suggesting that there are other or additional transcription factors critical for regulating hTERT expression.

Characterization of Thinopyrum distichum chromosomes using double fluorescence in situ hybridization, RFLP analysis of 5S and 26S rRNA, and C-banding of parents and addition lines

Genome ◽  
1997 ◽  
Vol 40 (5) ◽  
pp. 689-696 ◽  
Author(s):  
A Fominaya ◽  
S. Molnar ◽  
G. Fedak ◽  
K. C. Armstrong ◽  
N.-S. Kim ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
Chromosome Pair ◽  
Triticum Turgidum ◽  
5S Rrna ◽  
Polymorphism Analysis ◽  
Addition Lines ◽  
C Banding ◽  
26S Rrna

Diagnostic markers for eight Thinopyrum distichum addition chromosomes in Triticum turgidum were established using C-banding, in situ hybridization, and restriction fragment length polymorphism analysis. The C-band karyotype conclusively identified individual Th. distichum chromosomes and distinguished them from chromosomes of T. turgidum. Also, TaqI and BamHI restriction fragments containing 5S and 18S–5.8S–26S rRNA sequences were identified as positive markers specific to Th. distichum chromosomes. Simultaneous fluorescence in situ hybridization showed both 5S and 18S–5.8S–26S ribosomal RNA genes to be located on chromosome IV. Thinopyrum distichum chromosome VII carried only a 18S–5.8S–26S rRNA locus and chromosome pair II carried only a 5S rRNA locus. The arrangement of these loci on Th. distichum chromosome IV was different from that on wheat chromosome pair 1B. Two other unidentified Th. distichum chromosome pairs also carried 5S rRNA loci. The homoeologous relationship between Th. distichum chromosomes IV and VII and chromosomes of other members of the Triticeae was discussed by comparing results obtained using these physical and molecular markers.Key words: Triticum turgidum, homoeologous relationship, Triticeae, addition lines, NOR.

Nuclear receptor coactivators: the key to unlock chromatin

2005 ◽  
Vol 83 (4) ◽  
pp. 418-428 ◽  
Author(s):  
Wei Xu
Keyword(s):  
Nuclear Receptors ◽  
Nuclear Receptor ◽  
Chromatin Remodeling ◽  
Transcriptional Activation ◽  
Transcriptional Control ◽  
Biological Effects ◽  
Gene Activation ◽  
Nuclear Hormone Receptor ◽  
Nuclear Receptor Coactivators ◽  
Chromatin Remodeling Complex

The biological effects of hormones, ranging from organogenesis, metabolism, and proliferation, are transduced through nuclear receptors (NRs). Over the last decade, NRs have been used as a model to study transcriptional control. The conformation of activated NRs is favorable for the recruitment of coactivators, which promote transcriptional activation by directly communicating with chromatin. This review will focus on the function of different classes of coactivators and associated complexes, and on progress in our understanding of gene activation by NRs through chromatin remodeling.Key words: nuclear hormone receptor, p160 family of coactivators, histone modification, chromatin remodeling complex.

scholarly journals Genome-wide profiling of transcribed enhancers during macrophage activation

2017 ◽  
Author(s):  
Elena Denisenko ◽  
Reto Guler ◽  
Musa Mhlanga ◽  
Harukazu Suzuki ◽  
Frank Brombacher ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcriptional Activation ◽  
Large Scale ◽  
Transcriptional Control ◽  
Macrophage Activation ◽  
Transcriptional Responses ◽  
Protein Coding ◽  
Genome Wide ◽  
Ifn Γ ◽  
Cap Analysis

AbstractMacrophages are sentinel cells essential for tissue homeostasis and host defence. Owing to their plasticity, macrophages acquire a range of functional phenotypes in response to microenvironmental stimuli, of which M(IFN-γ) and M(IL-4/IL-13) are well-known for their opposing pro- and anti-inflammatory roles. Enhancers have emerged as regulatory DNA elements crucial for transcriptional activation of gene expression. Using cap analysis of gene expression and epigenetic data, we identify on large-scale transcribed enhancers in mouse macrophages, their time kinetics and target protein-coding genes. We observe an increase in target gene expression, concomitant with increasing numbers of associated enhancers and find that genes associated to many enhancers show a shift towards stronger enrichment for macrophage-specific biological processes. We infer enhancers that drive transcriptional responses of genes upon M(IFN-γ) and M(IL-4/IL-13) macrophage activation and demonstrate stimuli-specificity of regulatory associations. Finally, we show that enhancer regions are enriched for binding sites of inflammation-related transcription factors, suggesting a link between stimuli response and enhancer transcriptional control. Our study provides new insights into genome-wide enhancer-mediated transcriptional control of macrophage genes, including those implicated in macrophage activation, and offers a detailed genome-wide catalogue to further elucidate enhancer regulation in macrophages.

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