And-1 is required for the stability of histone acetyltransferase Gcn5

Abstract

Histone acetyltransferases (HATs) play a central role in the modification of chromatin as well as in pathogenesis of a broad set of diseases including cancers. Gcn5 is the first identified transcription-related histone acetyltransferase (HAT) that has been implicated in the regulation of diverse cellular functions. However, how Gcn5 proteins are regulated remains largely unknown. Here we show that And-1 (a HMG domain-containing protein) has remarkable capability to regulate the stability of Gcn5 proteins and thereby histone H3 acetylation. We find that And-1 forms a complex with both histone H3 and Gcn5. Downregulation of And-1 results in Gcn5 degradation, leading to the reduction of H3K9 and H3K56 acetylation. And-1 overexpression stabilizes Gcn5 through protein-protein interactions in vivo. Furthermore, And-1 expression is increased in cancer cells in a manner correlating with increased Gcn5 and H3K9Ac and H3K56Ac. Thus, our data reveal not only a functional link between Gcn5 and And-1 that is essential to regulate Gcn5 protein stability and histone H3 acetylation, but also a potential role of And-1 in cancer.

The Involvement of Acidic Nucleoplasmic DNA-binding Protein (And-1) in the Regulation of Prereplicative Complex (pre-RC) Assembly in Human Cells

“…Anti-PAN-MCM (559541) was from BD Biosciences Pharmingen. Anti-And-1 was produced as described previously (30).…”

“…Immunofluorescence assays were described previously (30). Chromatin fractionation assays were performed as described previously (32).…”

“…We and others recently found that unlike Xenopus, And-1 that is loaded onto chromatin at the onset of S phase, human And-1 is loaded onto chromatin in late mitosis (24,30), suggesting an important role of human And-1 in regulating chromatin function during late mitosis through G 1 phase. The fact that And-1 interacts with MCM2-7 proteins prompted us to investigate whether human And-1 regulates the association of MCM2-7 with chromatin.…”

“…Surprisingly, we and others (24,30) also have observed that human And-1 relocalizes onto chromatin in late mitosis, suggesting that human cells have a distinct mechanism governing the association of And-1 with chromatin. In an effort to elucidate the role of And-1 during this period of the mammalian cell cycle, we considered the possibility that human And-1 is recruited onto chromatin during late mitosis in order to play a role in regulating pre-RC assembly.…”

“…Other studies further indicate that And-1 is involved in the formation of the Cdc45-MCM2-7-GINS (Go, Ichi, Nii, and San) complex, stimulates the activities of DNA polymerases ␣ and ⑀, and couples MCM2-7 to DNA polymerase alpha (24 -28). More recently, we demonstrated that And-1 interacts with and maintains the stability of the histone acetyltransferase, Gcn5 (29,30). Thus, And-1 is an important protein that plays multiple roles in the regulation of chromatin function and DNA replication.…”