Journal of Biosciences

, Volume 4, Issue 4, pp 513–526

The mealybug chromosome system I: Unusual methylated bases and dinucleotides in DNA of aPlanococcus species

  • Dileep N. Deobagkar
  • K. Muralidharan
  • Sushilkumar G. Devare
  • Krishna K. Kalghatgi
  • H. Sharat Chandra
Article

Abstract

The methylation status of the nuclear DNA from a mealybug, aPlanococcus species, has been studied. Analysis of this DNA by High Performance Liquid Chromatography and Thin Layer Chromatography revealed the presence of significant amounts of 5-—methylcytosine. Since analysis of DNA methylation using the Msp I/Hpa II system showed only minor differences in susceptibility of the DNA to the two enzymes, it seemed possible that 5-methylcytosine (5mC) occurred adjacent to other nucleotides in addition to its usual position, next to guanosine. This was verified by dinucleotide analysis of DNA labelledin vitro by nick translation. These data show that the total amount of 5-methylcytosine in this DNA is slightly over 2.3 mol %, of which 0.61% occurs as the dinucleotide 5mCpG, 0.68% as 5mCpA, 0.59% as 5mCpT and 0.45% as 5mCpC. 5mCpG represents approximately 3.3% of all CpG dinucleotides. The experimental procedure would not have permitted the detection of 5mCp5mC, if it occurs in this system. Unusually high amounts of 6-methyladenine (approximately 4 mol %) and 7-methylguanine (approximately 2 mol %) were also detected, 6-methyladenine and 7-methylguanine occurred adjacent to all four nucleotides. The total G+C content was 33.7% as calculated from dinucleotide data and 32.9% as determined from melting profiles.

Keywords

Mealybug (Planococcuschromosome imprinting chromosome inactivation diffuse centromere DNA methylation 7-methylguanine 

Abbreviations used

5mC

5-Methylcytosine

6mA

6-methyladenine

7mG

7-methylguanine

PLC

high performance liquid chromatography

TLC

thin layer chromatography

UV

ultra-violet

dNTP

deoxynucleotide triphosphates

DEAE

diethylaminoethyl

Tris

Tris-(hydroxymethyl) amino methane

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Copyright information

© Indian Academy of Sciences 1982

Authors and Affiliations

  • Dileep N. Deobagkar
    • 1
  • K. Muralidharan
    • 1
  • Sushilkumar G. Devare
    • 1
    • 2
  • Krishna K. Kalghatgi
    • 1
    • 3
  • H. Sharat Chandra
    • 1
  1. 1.Microbiology and Cell Biology Laboratory ICMR Centre for Genetics and Cell BiologyIndian Institute of ScienceBangalore
  2. 2.Laboratory of Cellular and Molecular BiologyNational Cancer Institute, NIHUSA
  3. 3.Department of Chemical EngineeringYale UniversityNew HavenUSA

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