A functional N-terminal domain in C/EBPβ-LAP* is required for interacting with SWI/SNF and to repress Ric-8B gene transcription in osteoblasts.
A functional N-terminal domain in C/EBPβ-LAP* is required for interacting with SWI/SNF and to repress Ric-8B gene transcription in osteoblasts.
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DOI：
10.1002/jcp.24595
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发表时间：
2014-10
影响因子：
5.6
通讯作者：
Montecino, Martin
中科院分区：
文献类型：
--
作者：
Aguilar, Rodrigo;Grandy, Rodrigo;Meza, Daniel;Sepulveda, Hugo;Pihan, Philippe;van Wijnen, Andre J.;Lian, Jane B.;Stein, Gary S.;Stein, Janet L.;Montecino, Martin
染色质重塑复合体SWI/SnF和转录因子C/EBPβ在成骨细胞中起着关键作用，因为它们共同控制着许多与骨相关的靶基因的转录。最大的C/EBPβ亚型LAP*含有一个短的附加N-末端结构域，该结构域被认为在髓系细胞中介导该因子与SWI/Snf的相互作用。在这里，我们研究了C/EBPSWI-LAP*中功能N-末端与β/Snf结合的需要，并将该复合体招募到Ric-8B基因以介导转录抑制。我们发现在分化抑制Ric-8B表达的成骨细胞时，C/EBPβ-LAP*和SWI/Snf同时与Ric-8B启动子结合。这种Ric-8B表达的降低并不伴随着Ric-8B基因启动子序列上组蛋白乙酰化的显著变化。C/EBPβ-LAP*N末端(R3L)上的单个氨基酸变化抑制了C/EBPβ-LAP*-SWI/Snf的相互作用，也阻止了SWI/Snf在Ric-8B启动子上的募集以及C/EBPβ-LAP*依赖的Ric-8B基因的抑制。C/eBPβ-LAP*R3L蛋白在稳定表达的成骨细胞中可诱导表达，表明该突变蛋白与C/eBPβ-LAP*-靶启动子结合，并与内源性C/eBPβ因子竞争。综上所述，我们的结果表明，在成骨细胞中，C/EBPSIC-LAP*与β/Snf的相互作用和Ric-8B基因的抑制都需要一个功能性的N末端。
The chromatin remodeling complex SWI/SNF and the transcription factor C/EBPβ play critical roles in osteoblastic cells as they jointly control transcription of a number of bone-related target genes. The largest C/EBPβ isoform, LAP*, possesses a short additional N-terminal domain that has been proposed to mediate the interaction of this factor with SWI/SNF in myeloid cells. Here we examine the requirement of a functional N-terminus in C/EBPβ-LAP* for binding SWI/SNF and for recruiting this complex to the Ric-8B gene to mediate transcriptional repression. We find that both C/EBPβ-LAP* and SWI/SNF simultaneously bind to the Ric-8B promoter in differentiating osteoblasts that repress Ric-8B expression. This decreased expression of Ric-8B is not accompanied by significant changes in histone acetylation at the Ric-8B gene promoter sequence. A single aminoacid change at the C/EBPβ-LAP* N-terminus (R3L) that inhibits C/EBPβ-LAP*-SWI/SNF interaction, also prevents SWI/SNF recruitment to the Ric-8B promoter as well as C/EBPβ-LAP*-dependent repression of the Ric-8B gene. Inducible expression of the C/EBPβ-LAP*R3L protein in stably transfected osteoblastic cells demonstrates that this mutant protein binds to C/EBPβ-LAP*-target promoters and competes with the endogenous C/EBPβ factor. Together our results indicate that a functional N-terminus in C/EBPβ-LAP* is required for interacting with SWI/SNF and for Ric-8B gene repression in osteoblasts.
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影响因子：
5.6
作者：
Henriquez, Berta;Hepp, Matias;Merino, Paola;Sepulveda, Hugo;Van Wijnen, Andre J.;Lian, Jane B.;Stein, Gary S.;Stein, Janet L.;Montecino, Martin
通讯作者：
Montecino, Martin
影响因子：
4.8
作者：
Ohkawa, Yasuyuki;Yoshimura, Saori;Imbalzano, Anthony N.
通讯作者：
Imbalzano, Anthony N.
影响因子：
1.2
作者：
Maldonado-Agurto, R.;Toro, G.;Torrejon, M.
通讯作者：
Torrejon, M.
影响因子：
4.8
作者：
Villagra, Alejandro;Cruzat, Fernando;Montecino, Martin
通讯作者：
Montecino, Martin
影响因子：
2.9
作者：
Steinberg, Ximena P.;Hepp, Matias I.;Gutierrez, Jose L.
通讯作者：
Gutierrez, Jose L.