scholarly journals Sequence Elements in both the Intergenic Space and the 3′ Untranslated Region of the Crithidia fasciculata KAP3 Gene Are Required for Cell Cycle Regulation of KAP3 mRNA

2003 ◽  
Vol 2 (4) ◽  
pp. 671-677 ◽  
Author(s):  
Nuraly K. Avliyakulov ◽  
Jane C. Hines ◽  
Dan S. Ray
Keyword(s):  
Cell Cycle ◽  
Dna Binding ◽  
Binding Protein ◽  
Large Subunit ◽  
Dna Binding Protein ◽  
Mrna Levels ◽  
Crithidia Fasciculata ◽  
Consensus Sequences ◽  
Transcript Processing ◽  
Cycle Dependent

ABSTRACT mRNA levels of several Crithidia fasciculata genes involved in DNA metabolism have previously been found to cycle as cells progress through the cell cycle. Octamer consensus sequences in the 5′ untranslated regions (5′ UTRs) of these transcripts were shown to be required for cycling of these mRNAs. The KAP3 gene encodes a kinetoplast histone H1-like DNA binding protein, and its mRNA levels cycle in parallel with those of the kinetoplast DNA topoisomerase (TOP2), dihydrofolate reductase-thymidylate synthase (DHFR-TS), and the large subunit of the nuclear single-stranded DNA binding protein (RPA1). KAP3 mRNA contains two octamer consensus sequences in its 3′ UTR but none in its 5′ UTR. Mutation of these octamer sequences was not sufficient to prevent cycling of a sequence-tagged KAP3 mRNA expressed from a plasmid. Mutation of an octamer sequence contained on the precursor transcript but not on the mRNA, in addition to mutation of the two octamer sequences in the 3′ UTR, was necessary to abolish cycling of the mRNA. The requirement for a sequence not present on the mature mRNA indicates that regulation of the mRNA levels by the octamer sequences occurs at or prior to splicing of the transcript. Incompletely processed RNAs containing octamer sequences were also found to accumulate during the cell cycle when the mRNA levels were lowest. These RNA species hybridize to both the KAP3 coding sequence and that of the downstream drug resistance gene, indicating a lack of processing within the intergenic region separating these genes. We propose a cell cycle-dependent interference in transcript processing mediated by octamer consensus sequences as a mechanism contributing to the cycling of such transcripts.

scholarly journals Presence of a Poly(A) Binding Protein and Two Proteins with Cell Cycle-Dependent Phosphorylation in Crithidia fasciculata mRNA Cycling Sequence Binding Protein II

2004 ◽  
Vol 3 (5) ◽  
pp. 1185-1197 ◽  
Author(s):  
Bidyottam Mittra ◽  
Dan S. Ray
Keyword(s):  
Cell Cycle ◽  
Binding Protein ◽  
High Specificity ◽  
Binding Activity ◽  
Mrna Levels ◽  
Crithidia Fasciculata ◽  
Target Mrna ◽  
Cycle Dependent

ABSTRACT Crithidia fasciculata cycling sequence binding proteins (CSBP) have been shown to bind with high specificity to sequence elements present in several mRNAs that accumulate periodically during the cell cycle. The first described CSBP has subunits of 35.6 (CSBPA) and 42 kDa (CSBPB). A second distinct binding protein termed CSBP II has been purified from CSBPA null mutant cells, lacking both CSBPA and CSBPB proteins, and contains three major polypeptides with predicted molecular masses of 63, 44.5, and 33 kDa. Polypeptides of identical size were radiolabeled in UV cross-linking assays performed with purified CSBP II and 32P-labeled RNA probes containing six copies of the cycling sequence. The CSBP II binding activity was found to cycle in parallel with target mRNA levels during progression through the cell cycle. We have cloned genes encoding these three CSBP II proteins, termed RBP63, RBP45, and RBP33, and characterized their binding properties. The RBP63 protein is a member of the poly(A) binding protein family. Homologs of RBP45 and RBP33 proteins were found only among the kinetoplastids. Both RBP45 and RBP33 proteins and their homologs have a conserved carboxy-terminal half that contains a PSP1-like domain. All three CSBP II proteins show specificity for binding the wild-type cycling sequence in vitro. RBP45 and RBP33 are phosphoproteins, and RBP45 has been found to bind in vivo specifically to target mRNA containing cycling sequences. The levels of phosphorylation of both RBP45 and RBP33 were found to cycle during the cell cycle.

scholarly journals A new G-stretch-DNA-binding protein, Unichrom, displays cell-cycle-dependent expression in sea urchin embryos

2004 ◽  
Vol 46 (4) ◽  
pp. 335-341 ◽  
Author(s):  
Kosho Moritani ◽  
Hideki Tagashira ◽  
Taishin Shimotori ◽  
Naoaki Sakamoto ◽  
Shin Tanaka ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Binding ◽  
Sea Urchin ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Sea Urchin Embryos ◽  
Cycle Dependent

DNA-Binding Protein and the Cell Cycle in Cryptothecodinium cohnii

1973 ◽  
Vol 1 (6) ◽  
pp. 383-391 ◽  
Author(s):  
C.K. Franker ◽  
Candyce D. Prichard ◽  
Carol A. Lamden
Keyword(s):  
Cell Cycle ◽  
Dna Binding ◽  
Binding Protein ◽  
Dna Binding Protein

Cloning of a mitogen-inducible gene encoding a κB DNA-binding protein with homology to the rel oncogene and to cell-cycle motifs

Nature ◽  
1990 ◽  
Vol 348 (6296) ◽  
pp. 76-80 ◽  
Author(s):  
Vincent Bours ◽  
Juanita Villalobos ◽  
Parris R. Burd ◽  
Kathleen Kelly ◽  
Ulrich Siebenlist
Keyword(s):  
Cell Cycle ◽  
Dna Binding ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Gene Encoding ◽  
Inducible Gene

scholarly journals A mutation in the gene encoding the Saccharomyces cerevisiae single-stranded DNA-binding protein Rfa1 stimulates a RAD52-independent pathway for direct-repeat recombination.

1995 ◽  
Vol 15 (3) ◽  
pp. 1632-1641 ◽  
Author(s):  
J Smith ◽  
R Rothstein
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Binding ◽  
Binding Protein ◽  
Large Subunit ◽  
Direct Repeat ◽  
Fold Increase ◽  
Dna Binding Protein ◽  
Yeast Saccharomyces Cerevisiae ◽  
Single Stranded Dna ◽  
Mutant Strains

In the yeast Saccharomyces cerevisiae, recombination between direct repeats is synergistically reduced in rad1 rad52 double mutants, suggesting that the two genes define alternate recombination pathways. Using a classical genetic approach, we searched for suppressors of the recombination defect in the double mutant. One mutation that restores wild-type levels of recombination was isolated. Cloning by complementation and subsequent physical and genetic analysis revealed that it maps to RAF1. This locus encodes the large subunit of the single-stranded DNA-binding protein complex, RP-A, which is conserved from S. cerevisiae to humans. The rfa1 mutation on its own causes a 15-fold increase in direct-repeat recombination. However, unlike most other hyperrecombination mutations, the elevated levels in rfa1 mutants occur independently of RAD52 function. Additionally, rfa1 mutant strains grow slowly, are UV sensitive, and exhibit decreased levels of heteroallelic recombination. DNA sequence analysis of rfa1 revealed a missense mutation that alters a conserved residue of the protein (aspartic acid 228 to tyrosine [D228Y]). Biochemical analysis suggests that this defect results in decreased levels of RP-A in mutant strains. Overexpression of the mutant subunit completely suppresses the UV sensitivity and partially suppresses the recombination phenotype. We propose that the defective complex fails to interact properly with components of the repair, replication, and recombination machinery. Further, this may permit the bypass of the recombination defect of rad1 rad52 mutants by activating an alternative single-stranded DNA degradation pathway.

scholarly journals A Novel DNA-binding Protein Coordinates Asymmetric Chromosome Replication and Chromosome Partitioning

2016 ◽  
Author(s):  
James A. Taylor ◽  
Gaël Panis ◽  
Patrick H. Viollier ◽  
Gregory T. Marczynski
Keyword(s):  
Cell Cycle ◽  
Dna Binding ◽  
Replication Origin ◽  
Caulobacter Crescentus ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Chromosome Replication ◽  
Chromosome Partitioning ◽  
Chromosome Separation

AbstractBacterial chromosome replication is regulated from a single replication origin (ori) that receives cell cycle signals. Following replication, bacteria often use theparABSpartition system with a centromere-likeparSlocus to place the chromosomes into the daughter cells. Our knowledge of cell cycle regulation is incomplete and we searched for novel regulators of chromosome replication. Here we show that in the cell cycle modelCaulobacter crescentusa novel DNA-binding protein promotes both the initiation of chromosome replication and the earliest step of chromosome partitioning. We used biochemical fractionation to identify a protein (OpaA) that preferentially binds to mutatedoriDNA that also increasesori-plasmid replicationin vivo. OpaA represents a previously unknown class of DNA-binding proteins.opaAgene expression is essential and sufficient OpaA levels are required for the correct timing of chromosome replication. Whole genome ChIP-seq identified the genomic binding sites for OpaA, with the strongest associations at theparABSlocus nearori. Using molecular-genetic and fluorescence microscopy experiments, we showed that OpaA also promotes the first step of chromosome partitioning, the initial separation of the duplicatedparSloci followingorireplication. This separation occurs before theparABSmechanism and it coincides with the regulatory step that splits the symmetry of the chromosomes so that they are placed at distinct cell-poles which develop into replicating and non-replicating cell-types. We propose that OpaA coordinates replication with the poorly understood mechanism of early chromosome separation.opaAlethal suppressor and antibiotic experiments argue that future studies be focused on the mechanistic roles for transcription and translation at this critical step of the cell cycle.Author SummaryLike all organisms, bacteria must replicate their chromosomes and move them into the newly dividing cells. Eukaryotes use non-overlapping phases, first for chromosome replication (S-phase) followed by mitosis (M-phase) when the completely duplicated chromosomes are separated. However, bacteria combine both phases so chromosome replication and chromosome separation (termed chromosome “partitioning”) overlap. In many bacteria, includingCaulobacter crescentus, chromosome replication initiates from a single replication origin (ori) and the first duplicated regions of the chromosome immediately begin “partitioning” towards the cell poles long before the whole chromosome has finished replication. This partitioning movement uses the centromere-like DNA called“parS”that is located near theori. Here we identify a completely novel type of DNA-binding protein called OpaA and we show that it acts at bothoriandparS. The timing and coordination of overlapping chromosome replication and partitioning phases is a special regulatory problem for bacteria. We further demonstrate that OpaA is selectively required for the initiation of chromosome replication atoriand likewise that OpaA is selectively required for the initial partitioning ofparS. Therefore, we propose that OpaA is a novel regulator that coordinates chromosome replication with the poorly understood mechanism of early chromosome separation.

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