CBX3
Description
The CBX3 (chromobox 3) is a protein-coding gene located on chromosome 7.
Chromobox protein homolog 3 is a protein that is encoded by the CBX3 gene in humans. At the nuclear envelope, the nuclear lamina and heterochromatin are adjacent to the inner nuclear membrane. The protein encoded by this gene binds DNA and is a component of heterochromatin. This protein also can bind lamin B receptor, an integral membrane protein found in the inner nuclear membrane. The dual binding functions of the encoded protein may explain the association of heterochromatin with the inner nuclear membrane. Two transcript variants encoding the same protein but differing in the 5' UTR, have been found for this gene. CBX3 has been shown to interact with PIM1, Ki-67, Lamin B receptor, CBX5 and CBX1.
CBX3 plays a role in transcriptional silencing by binding to histone H3 tails methylated at Lys-9, leading to epigenetic repression. It may help attach heterochromatin to the inner nuclear membrane through its interaction with lamin B receptor (LBR). CBX3 is involved in forming functional kinetochores by interacting with MIS12 complex proteins. It contributes to converting local chromatin into a repressive state through H3 Lys-9 trimethylation and recruits methyltransferases SUV39H1 and/or SUV39H2 to circadian target genes via the PER complex. Additionally, CBX3 mediates the recruitment of NIPBL to sites of DNA damage at double-strand breaks (DSBs).
CBX3 is also known as HECH, HP1-GAMMA, HP1Hs-gamma, HP1gamma.
