Trithorax and dCBP acting in a complex to maintain expression of a homeotic gene.
Trithorax (Trx) is a member of the trithorax group (trxG) of epigenetic regulators, which is required to maintain active states of Hox gene expression during development. We have purified from Drosophila embryos a trithorax acetylation complex (TAC1) that contains Trx, dCBP, and Sbf1. Like CBP, TAC1 acetylates core histones in nucleosomes, suggesting that this activity may be important for epigenetic maintenance of gene activity. dCBP and Sbf1 associate with specific sites on salivary gland polytene chromosomes, colocalizing with many Trx binding sites. One of these is the site of the Hox gene Ultrabithorax (Ubx). Mutations in either trx or the gene encoding dCBP reduce expression of the endogenous Ubx gene as well as of transgenes driven by the bxd regulatory region of Ubx. Thus Trx, dCBP, and Sbf1 are closely linked, physically and functionally, in the maintenance of Hox gene expression.
Petruk
S
S
Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA.
Sedkov
Y
Y
Smith
S
S
Tillib
S
S
Kraevski
V
V
Nakamura
T
T
Canaani
E
E
Croce
C M
CM
Mazo
A
A
D000107:Acetylation; D000123:Acetyltransferases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D030801:Animals, Genetically Modified; D001665:Binding Sites; D050882:CREB-Binding Protein; D002352:Carrier Proteins / Q000378:metabolism; D002846:Chromatography, Affinity; D002875:Chromosomes / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D004330:Drosophila / Q000196:embryology / Q000235:genetics*; D029721:Drosophila Proteins; D004625:Embryo, Nonmammalian / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D005801:Genes, Homeobox; D017344:Genes, Insect; D051548:Histone Acetyltransferases; D006657:Histones / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics*; D047908:Intracellular Signaling Peptides and Proteins; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D009707:Nucleosomes / Q000378:metabolism; D020218:Response Elements; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors; D019076:Transgenes
D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D006657:Histones; D018398:Homeodomain Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D009707:Nucleosomes; C111446:SBF1 protein, human; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C063460:Trl protein, Drosophila; C066177:Ubx protein, Drosophila; D000123:Acetyltransferases; D050882:CREB-Binding Protein; D051548:Histone Acetyltransferases