Epigenetic regulation of facultative heterochromatinisation in Planococcus citri via the Me(3)K9H3-HP1-Me(3)K20H4 pathway.
Using RNA interference (RNAi) we have conducted a functional analysis of the HP1-like chromobox gene pchet2 during embryogenesis of the mealybug Planococcus citri. Knocking down pchet2 expression results in decondensation of the male-specific chromocenter that normally arises from the developmentally-regulated facultative heterochromatinisation of the paternal chromosome complement. Together with the disappearance of the chromocenter the staining levels of two associated histone modifications, tri-methylated lysine 9 of histone H3 [Me(3)K9H3] and tri-methylated lysine 20 of histone H4 [Me(3)K20H4], are reduced to undetectable levels. Embryos treated with double-stranded RNA (dsRNA) targeting pchet2 also exhibit chromosome abnormalities, such as aberrant chromosome condensation, and also the presence of metaphases that contain 'lagging' chromosomes. We conclude that PCHET2 regulates chromosome behavior during metaphase and is a crucial component of a Me(3)K9H3-HP1-Me(3)K20H4 pathway involved in the facultative heterochromatinisation of the (imprinted) paternal chromosome set.
Bongiorni
Silvia
S
Department of Agrobiologia e Agrochimica, University of Tuscia, 01100 Viterbo, Italy.
Pasqualini
Barbara
B
Taranta
Monia
M
Singh
Prim B
PB
Prantera
Giorgio
G
D000818:Animals; D002869:Chromosome Aberrations; D004625:Embryo, Nonmammalian / Q000502:physiology; D044127:Epigenesis, Genetic; D018392:Genomic Imprinting; D006430:Hemiptera / Q000235:genetics / Q000502:physiology*; D006570:Heterochromatin / Q000502:physiology*; D006657:Histones / Q000737:chemistry / Q000502:physiology*; D019476:Insect Proteins / Q000235:genetics / Q000502:physiology*; D008239:Lysine / Q000737:chemistry; D008297:Male; D008677:Metaphase / Q000502:physiology*; D008745:Methylation; D009687:Nuclear Proteins / Q000235:genetics / Q000502:physiology*; D012330:RNA, Double-Stranded / Q000378:metabolism; D015398:Signal Transduction
D006570:Heterochromatin; D006657:Histones; D019476:Insect Proteins; D009687:Nuclear Proteins; D012330:RNA, Double-Stranded; C075671:pchet2 protein, Planococcus citri; D008239:Lysine