Biomaterial Database

[Distribution of 5-methylcytosine in pyrimidine oligonucleotides of higher plant DNA]. 1978

M Dokhiem, and G E Sulimova, and B F Vaniushin

The level of pyrimidine clusters (isopliths) and distribution of 5-methylcytosine in DNAs of some archegonial (ferns, ginkgo) and flowering (cordyline, tulip, wheat) plants has been studied. DNA from Cordyline australis (Liliaceae) is one of the GC-type (GC = 57.5 mol.%), has very low methylation level (amount of m5C is about 1 mol.%) and significantly differs from other species DNAs studied in terms of pyrimidine distribution patterns, i.e. amount of dipyrimidine fragments is higher than that of monopyrimidine ones. All other plant DNAs under study are of the AT-type, have similar pyrimidine distribution patterns and are characterized by high degree of pyrimidine blocking; specific differences in the level (approximately 10-fold) and type of genome methylation are found. In all DNAs studied 5-methylcytosine is unevenly distributed in pyrimidine isopliths: the degree of cytosine methylation [m5C(C+m5C)] is decreased with an increase in the length of isopliths, irrespective of the ratio of thymine and cytosine residues. 5-methylcytosine is mainly accumulated in mono- and dipyrimidine fragments (60--68%). Specific differences in 5-methylcytosine content in trinucleotides and long-chain pyrimidine oligonucleotides are revealed.

UI	MeSH Term	Description	Entries
D008745	Methylation	Addition of methyl groups. In histo-chemistry methylation is used to esterify carboxyl groups and remove sulfate groups by treating tissue sections with hot methanol in the presence of hydrochloric acid. (From Stedman, 25th ed)	Methylations
D009838	Oligodeoxyribonucleotides	A group of deoxyribonucleotides (up to 12) in which the phosphate residues of each deoxyribonucleotide act as bridges in forming diester linkages between the deoxyribose moieties.	Oligodeoxynucleotide,Oligodeoxyribonucleotide,Oligodeoxynucleotides
D009841	Oligonucleotides	Polymers made up of a few (2-20) nucleotides. In molecular genetics, they refer to a short sequence synthesized to match a region where a mutation is known to occur, and then used as a probe (OLIGONUCLEOTIDE PROBES). (Dorland, 28th ed)	Oligonucleotide
D010944	Plants	Multicellular, eukaryotic life forms of kingdom Plantae. Plants acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations. It is a non-taxonomical term most often referring to LAND PLANTS. In broad sense it includes RHODOPHYTA and GLAUCOPHYTA along with VIRIDIPLANTAE.	Plant
D003596	Cytosine	A pyrimidine base that is a fundamental unit of nucleic acids.
D004247	DNA	A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).	DNA, Double-Stranded,Deoxyribonucleic Acid,ds-DNA,DNA, Double Stranded,Double-Stranded DNA,ds DNA