Modulation of DNA methyltransferase during the life cycle of a mealybug Planococcus lilacinus

Abstract

The levels of de novo DNA methyltransferase were studied during the development of a mealybug, PIanococcus lilacinus. No enzyme activity could be detected in extracts from second instar females. But the enzyme occurs at high levels in third instar females and is maintained at that level during fourth instar when gametogenesis, fertilization and chromosome imprinting occur. These results suggest a developmental stage-specific modulation of levels of DNA methyltransferase. Assays with synthetic polymers showed that the enzyme can methylate not only polymers containing GpG but also those containing CpA and CpI.

Detection of a CpA methylase in an insect system: characterization and substrate specificity

“…The activity of DNA methylase varies during different stages of development of the mealybug, however, the ability to methylate CpA sequences is detectable at all stages at which CpG methylation is detected [20]. Therefore it appears that CpA methylation may be an important post-replicative modification of DNA in this system.…”

“…KC1 at 50 mM or 150 mM was added to the assay mixture for native and denatured DNA substrates respectively. The reaction was carried out at 37 ° C for 30 min and monitored as described before [20].…”