Different Effects of Histone H1 on <i>de Novo</i> DNA Methylation <i>in Vitro</i> Depend on both the DNA Base Composition and the DNA Methyltransferase

Carotti, Daniela; Funiciello, Salvatore; Lavia, Patrizia; Caiafa, Paola; Strom, Roberto

doi:10.1021/bi9606051

Cited by 6 publications

(7 citation statements)

References 51 publications

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“…The DNMT1-PCNA interaction may allow for the newly synthesized daughter strands to be rapidly remethylated before being packaged into chromatin. This may be essential for maintenance of proper methylation patterns since histone HI, one of the principal chromatin organizing proteins, has been shown to inhibit DNA methylation (Carotti et al, 1996). Loss of p21, either by mutation of the p21 gene itself or loss of p53, which activates p21 expression in response to DNA damage, is a common event in cancer .…”

Section: Pcnamentioning

confidence: 99%

DNA methylation, methyltransferases, and cancer

2001

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The ®eld of epigenetics has recently moved to the forefront of studies relating to diverse processes such as transcriptional regulation, chromatin structure, genome integrity, and tumorigenesis. Recent work has revealed how DNA methylation and chromatin structure are linked at the molecular level and how methylation anomalies play a direct causal role in tumorigenesis and genetic disease. Much new information has also come to light regarding the cellular methylation machinery, known as the DNA methyltransferases, in terms of their roles in mammalian development and the types of proteins they are known to interact with. This information has forced a new view for the role of DNA methyltransferases. Rather than enzymes that act in isolation to copy methylation patterns after replication, the types of interactions discovered thus far indicate that DNA methyltransferases may be components of larger complexes actively involved in transcriptional control and chromatin structure modulation. These new ®ndings will likely enhance our understanding of the myriad roles of DNA methylation in disease as well as point the way to novel therapies to prevent or repair these defects. Oncogene (2001) 20, 3139 ± 3155.

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Section: Pcnamentioning

confidence: 99%

DNA methylation, methyltransferases, and cancer

2001

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“…This has been exemplified by spermine (36)(37)(38) and PCPs (39), in particular, PL, which appears to have modes of DNA binding similar to H1 linker histone (40,41). The X-ray crystal structure of H1 linker histone (42) and circular dichroism studies of drug binding to DNA (43) indicate that positively charged groups of histones are inserted into the DNA minor groove.…”

Section: Model Of Interactions Between Dna and Pcpsmentioning

confidence: 99%

Protection of DNA against Direct Radiation Damage by Complex Formation with Positively Charged Polypeptides

2006

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Radioprotection of DNA from direct-type radiation damage by histones has been studied in model systems using complexes of positively charged polypeptides (PCPs) with DNA. PCPs bind to DNA via ionic interactions mimicking the mode of DNA-histone binding. Direct radiation damage to DNA in films of DNA-PCP complexes was quantified as unaltered base release, which correlates closely with DNA strand breaks. All types of PCPs tested protected DNA from radiation, with the maximum radioprotection being approximately 2.5-fold compared with non-complexed DNA. Conformational changes of the DNA induced by PCPs or repair of free radical damage on the DNA sugar moiety by PCPs are considered the most feasible mechanisms of radioprotection of DNA. The degree of radioprotection of DNA by polylysine (PL) increased dramatically on going from pure DNA to a molar ratio of PL monomer:DNA nucleotide ~1:2, while a further increase in the PL:DNA ratio did not offer more radioprotection. This concentration dependence is in agreement with the model of PCP binding to DNA that assumes preferential binding of positively charged side groups to DNA phosphates in the minor groove, so that the maximum occupancy of all minor-groove PCP binding sites is at a molar ratio of PCP:DNA = 1:2.

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“…However, gel retardation analyses indicate that our enzyme preparation was free from Htf9-specific or Sp1 binding activities [data not shown; also see Carotti et al (1989Carotti et al ( , 1996]. …”

Section: Effect Of Pre-methylation On In Vitro Methylation Of Cpgmentioning

confidence: 99%

Influence of Pre-existing Methylation on the de Novo Activity of Eukaryotic DNA Methyltransferase

Carotti¹,

Funiciello²,

Palitti³

et al. 1998

Biochemistry

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Aberrant de novo methylation of CpG island DNA sequences has been observed in cultured cell lines or upon malignant transformation, but the mechanisms underlying this phenomenon are poorly understood. Using eukaryotic DNA (cytosine-5)-methyltransferase (of both human and murine origin), we have studied the in vitro methylation pattern of three CpG islands. Such sequences are intrinsically poor substrates of the enzyme, yet are efficiently methylated when a small amount of 5-methylcytosine is randomly introduced by the M.SssI prokaryotic DNA (cytosine-5)-methyltransferase prior to in vitro methylation by the eukaryotic enzyme. A stimulation was also found with several other double-stranded DNA substrates, either natural or of synthetic origin, such as poly(dG-dC).poly(dG-dC). An A + T-rich plasmid, pHb beta 1S, showed an initial stimulation, followed by a severe inhibition of the activity of DNA (cytosine-5)-methyltransferase. Methylation of poly(dI-dC).poly(dI-dC) was instead inhibited by pre-existing 5-methylcytosines. The extent of stimulation observed with poly(dG-dC).poly(dG-dC) depends on both the number and the distribution of the 5-methylcytosine residues, which probably must not be too closely spaced for the stimulatory effect to be exerted. The activity of the M.SssI prokaryotic DNA methyltransferase was not stimulated, but was inhibited by pre-methylation on either poly(dG-dC).poly(dG-dC) or poly(dI-dC).poly(dI-dC). The prokaryotic and eukaryotic DNA methyltransferases also differed in sensitivity to poly(dG-m5dC).poly(dG-m5dC), which is highly inhibitory for eukaryotic enzymes and almost ineffective on prokaryotic enzymes.

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Different Effects of Histone H1 on de Novo DNA Methylation in Vitro Depend on both the DNA Base Composition and the DNA Methyltransferase

Cited by 6 publications

References 51 publications

DNA methylation, methyltransferases, and cancer

DNA methylation, methyltransferases, and cancer

Protection of DNA against Direct Radiation Damage by Complex Formation with Positively Charged Polypeptides

Influence of Pre-existing Methylation on the de Novo Activity of Eukaryotic DNA Methyltransferase

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