Maintenance of Hox gene expression patterns.
Once established, homeotic gene (Hox) expression is maintained in the original pattern by Polycomb-group (PcG) and trithorax-group (trxG) proteins therefore named maintenance proteins (MPs). PcG and trxG proteins maintain silencing and activation of Hox and many other genes, respectively. We provide here a brief overview of genetics and molecular biology of these proteins and of a third class of proteins termed Enhancers of Trithorax and Polycomb (ETP) that are required for both maintenance of silencing and activation of Hox genes. We examine the recruitment of MPs onto maintenance elements (MEs), their role in the regulation of transcription and the epigenetic marks that could provide maintenance. Lastly, we discuss two important roles of PcG proteins in replication of DNA and stem cell renewal and maintenance.
Beck
Samantha
S
Molecular Epigenetics Group, Department of Zoology, Life Sciences Center, University of British Columbia, Vancouver, British Columbia, Canada.
Faradji
Floria
F
Brock
Hugh
H
Peronnet
Frédérique
F
D000818:Animals; D002843:Chromatin / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D044127:Epigenesis, Genetic; D018507:Gene Expression Regulation, Developmental; D020868:Gene Silencing; D005801:Genes, Homeobox; D006801:Humans; D063146:Polycomb-Group Proteins; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D020218:Response Elements; D013234:Stem Cells / Q000502:physiology
D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D029721:Drosophila Proteins; D063146:Polycomb-Group Proteins; D012097:Repressor Proteins; C512571:trx protein, Drosophila