Heterochromatin protein 1 (HP1) connects the FACT histone chaperone complex to the phosphorylated CTD of RNA polymerase II.
Heterochromatin protein 1 (HP1) is well known as a silencing protein found at pericentric heterochromatin. Most eukaryotes have at least three isoforms of HP1 that play differential roles in heterochromatin and euchromatin. In addition to its role in heterochromatin, HP1 proteins have been shown to function in transcription elongation. To gain insights into the transcription functions of HP1, we sought to identify novel HP1-interacting proteins. Biochemical and proteomic approaches revealed that HP1 interacts with the histone chaperone complex FACT (facilitates chromatin transcription). HP1c interacts with the SSRP1 (structure-specific recognition protein 1) subunit and the intact FACT complex. Moreover, HP1c guides the recruitment of FACT to active genes and links FACT to active forms of RNA polymerase II. The absence of HP1c partially impairs the recruitment of FACT into heat-shock loci and causes a defect in heat-shock gene expression. Thus, HP1c functions to recruit the FACT complex to RNA polymerase II.
Kwon
So Hee
SH
Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA.
Florens
Laurence
L
Swanson
Selene K
SK
Washburn
Michael P
MP
Abmayr
Susan M
SM
Workman
Jerry L
JL
D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006609:High Mobility Group Proteins / Q000378:metabolism; D056488:Histone Chaperones / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D020033:Protein Isoforms; D012319:RNA Polymerase II / Q000378:metabolism*; D020079:Terminal Repeat Sequences; D035602:Transcriptional Elongation Factors / Q000378:metabolism
D002352:Carrier Proteins; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; C518656:FACT protein, Drosophila; D006360:Heat-Shock Proteins; D006609:High Mobility Group Proteins; D056488:Histone Chaperones; D020033:Protein Isoforms; C489543:SSRP protein, Drosophila; D035602:Transcriptional Elongation Factors; C452193:heterochromatin protein 1, Drosophila; D012319:RNA Polymerase II