scholarly journals TEM1 combinatorially binds to FLOWERING LOCUS T and recruits a Polycomb factor to repress the floral transition in Arabidopsis

2021 ◽  
Vol 118 (35) ◽  
pp. e2103895118
Author(s):  
Hongmiao Hu ◽  
Shu Tian ◽  
Guohui Xie ◽  
Rui Liu ◽  
Nana Wang ◽  
...  

Arabidopsis TEMPRANILLO 1 (TEM1) is a transcriptional repressor that participates in multiple flowering pathways and negatively regulates the juvenile-to-adult transition and the flowering transition. To understand the molecular basis for the site-specific regulation of FLOWERING LOCUS T (FT) by TEM1, we determined the structures of the two plant-specific DNA-binding domains in TEM1, AP2 and B3, in complex with their target DNA sequences from the FT gene 5′-untranslated region (5′-UTR), revealing the molecular basis for TEM1 specificity for its DNA targets. In vitro binding assays revealed that the combination of the AP2 and B3 binding sites greatly enhanced the overall binding of TEM1 to the FT 5′-UTR, indicating TEM1 combinatorically recognizes the FT gene 5′-UTR. We further showed that TEM1 recruits the Polycomb repressive complex 2 (PRC2) to the FT 5′-UTR. The simultaneous binding of the TEM1 AP2 and B3 domains to FT is necessary for deposition of H3K27me3 at the FT 5′-UTR and for the flowering repressor function of TEM1. Overall, our data suggest that the combinatorial recognition of FT 5′-UTR by TEM1 ensures H3K27me3 deposition to precisely regulate the floral transition.

1987 ◽  
Vol 7 (12) ◽  
pp. 4582-4584 ◽  
Author(s):  
L Dailey ◽  
S B Roberts ◽  
N Heintz

Specific DNA-binding and in vitro transcription activities of H4TF-1 and H4TF-2 are inactivated by chelating agents. Binding activity is restored by addition of Zn2+, and H4TF-2 is also reactivated by Fe2+. In contrast, preformed factor-DNA complexes are resistant to chelators. Therefore, metal ions are a required component of the H4TF-1 and H4TF-2 DNA-binding domains.


Development ◽  
1996 ◽  
Vol 122 (9) ◽  
pp. 2639-2650 ◽  
Author(s):  
S. Jun ◽  
C. Desplan

The Pax proteins are a family of transcriptional regulators involved in many developmental processes in all higher eukaryotes. They are characterized by the presence of a paired domain (PD), a bipartite DNA binding domain composed of two helix-turn-helix (HTH) motifs, the PAI and RED domains. The PD is also often associated with a homeodomain (HD) which is itself able to form homo- and hetero-dimers on DNA. Many of these proteins therefore contain three HTH motifs each able to recognize DNA. However, all PDs recognize highly related DNA sequences, and most HDs also recognize almost identical sites. We show here that different Pax proteins use multiple combinations of their HTHs to recognize several types of target sites. For instance, the Drosophila Paired protein can bind, in vitro, exclusively through its PAI domain, or through a dimer of its HD, or through cooperative interaction between PAI domain and HD. However, prd function in vivo requires the synergistic action of both the PAI domain and the HD. Pax proteins with only a PD appear to require both PAI and RED domains, while a Pax-6 isoform and a new Pax protein, Lune, may rely on the RED domain and HD. We propose a model by which Pax proteins recognize different target genes in vivo through various combinations of their DNA binding domains, thus expanding their recognition repertoire.


1987 ◽  
Vol 7 (12) ◽  
pp. 4582-4584
Author(s):  
L Dailey ◽  
S B Roberts ◽  
N Heintz

Specific DNA-binding and in vitro transcription activities of H4TF-1 and H4TF-2 are inactivated by chelating agents. Binding activity is restored by addition of Zn2+, and H4TF-2 is also reactivated by Fe2+. In contrast, preformed factor-DNA complexes are resistant to chelators. Therefore, metal ions are a required component of the H4TF-1 and H4TF-2 DNA-binding domains.


2000 ◽  
Vol 20 (6) ◽  
pp. 2087-2097 ◽  
Author(s):  
Najet Amar ◽  
Francine Messenguy ◽  
Mohamed El Bakkoury ◽  
Evelyne Dubois

ABSTRACT Repression of arginine anabolic genes and induction of arginine catabolic genes are mediated by a three-component protein complex, interacting with specific DNA sequences in the presence of arginine. Although ArgRI and Mcm1, two MADS-box proteins, and ArgRII, a zinc cluster protein, contain putative DNA binding domains, alone they are unable to bind the arginine boxes in vitro. Using purified glutathioneS-transferase fusion proteins, we demonstrate that ArgRI and ArgRII1-180 or Mcm1 and ArgRII1-180 are able to reconstitute an arginine-dependent binding activity in mobility shift analysis. Binding efficiency is enhanced when the three recombinant proteins are present simultaneously. At physiological concentration, the full-length ArgRII is required to fulfill its functions; however, when ArgRII is overexpressed, the first 180 amino acids are sufficient to interact with ArgRI, Mcm1, and arginine, leading to the formation of an ArgR-Mcm1-DNA complex. Several lines of evidence indicate that ArgRII is the sensor of the effector arginine and that the binding site of arginine would be the region downstream from the zinc cluster, sharing some identity with the arginine binding domain of bacterial arginine repressors.


2005 ◽  
Vol 79 (13) ◽  
pp. 8661-8664 ◽  
Author(s):  
Stephen Schuck ◽  
Arne Stenlund

ABSTRACT Viral initiator proteins are polypeptides that form oligomeric complexes on the origin of DNA replication (ori). These complexes carry out a multitude of functions related to initiation of DNA replication, and although many of these functions have been characterized biochemically, little is understood about how the complexes are assembled. Here we demonstrate that loss of one particular interaction, the dimerization between E1 DNA binding domains, has a severe effect on DNA replication in vivo but has surprisingly modest effects on most individual biochemical activities in vitro. We conclude that the dimer interaction is primarily required for initial recognition of ori.


1993 ◽  
Vol 13 (2) ◽  
pp. 852-860
Author(s):  
M B Toledano ◽  
D Ghosh ◽  
F Trinh ◽  
W J Leonard

We previously reported that either oxidation or alkylation of NF-kappa B in vitro abrogates DNA binding. We used this phenomenon to help elucidate structural determinants of NF-kappa B binding. We now demonstrate that Cys-62 of NF-kappa B p50 mediates the redox effect and lies within an N-terminal region required for DNA binding but not for dimerization. Several point mutations in this region confer a transdominant negative binding phenotype to p50. The region is highly conserved in all Rel family proteins, and we have determined that it is also critical for DNA binding of NF-kappa B p65. Replacement of the N-terminal region of p65 with the corresponding region from p50 changes its DNA-binding specificity towards that of p50. These data suggest that the N-terminal regions of p50 and p65 are critical for DNA binding and help determine the DNA-binding specificities of p50 and p65. We have defined within the N-terminal region a sequence motif, R(F/G)(R/K)YXCE, which is present in Rel family proteins and also in zinc finger proteins capable of binding to kappa B sites. The potential significance of this finding is discussed.


1992 ◽  
Vol 12 (7) ◽  
pp. 3006-3014 ◽  
Author(s):  
E A Golemis ◽  
R Brent

Many studies of transcription activation employ fusions of activation domains to DNA binding domains derived from the bacterial repressor LexA and the yeast activator GAL4. Such studies often implicitly assume that DNA binding by the chimeric proteins is equivalent to that of the protein donating the DNA binding moiety. To directly investigate this issue, we compared operator binding by a series of LexA-derivative proteins to operator binding by native LexA, by using both in vivo and in vitro assays. We show that operator binding by many proteins such as LexA-Myc, LexA-Fos, and LexA-Bicoid is severely impaired, while binding of other LexA-derivative proteins, such as those that carry bacterially encoded acidic sequences ("acid blobs"), is not. Our results also show that DNA binding by LexA derivatives that contain the LexA carboxy-terminal dimerization domain (amino acids 88 to 202) is considerably stronger than binding by fusions that lack it and that heterologous dimerization motifs cannot substitute for the LexA88-202 function. These results suggest the need to reevaluate some previous studies of activation that employed LexA derivatives and modifications to recent experimental approaches that use LexA and GAL4 derivatives to detect and study protein-protein interactions.


2004 ◽  
Vol 24 (8) ◽  
pp. 3387-3395 ◽  
Author(s):  
Helle F. Jørgensen ◽  
Ittai Ben-Porath ◽  
Adrian P. Bird

ABSTRACT MBD1 is a vertebrate methyl-CpG binding domain protein (MBD) that can bring about repression of methylated promoter DNA sequences. Like other MBD proteins, MBD1 localizes to nuclear foci that in mice are rich in methyl-CpG. In methyl-CpG-deficient mouse cells, however, Mbd1 remains localized to heterochromatic foci whereas other MBD proteins become dispersed in the nucleus. We find that Mbd1a, a major mouse isoform, contains a CXXC domain (CXXC-3) that binds specifically to nonmethylated CpG, suggesting an explanation for methylation-independent localization. Transfection studies demonstrate that the CXXC-3 domain indeed targets nonmethylated CpG sites in vivo. Repression of nonmethylated reporter genes depends on the CXXC-3 domain, whereas repression of methylated reporters requires the MBD. Our findings indicate that MBD1 can interpret the CpG dinucleotide as a repressive signal in vivo regardless of its methylation status.


2014 ◽  
Vol 2014 ◽  
pp. 1-27 ◽  
Author(s):  
Christian Bach ◽  
William Sherman ◽  
Jani Pallis ◽  
Prabir Patra ◽  
Hassan Bajwa

Zinc finger nucleases (ZFNs) are associated with cell death and apoptosis by binding at countless undesired locations. This cytotoxicity is associated with the binding ability of engineered zinc finger domains to bind dissimilar DNA sequences with high affinity. In general, binding preferences of transcription factors are associated with significant degenerated diversity and complexity which convolutes the design and engineering of precise DNA binding domains. Evolutionary success of natural zinc finger proteins, however, evinces that nature created specific evolutionary traits and strategies, such as modularity and rank-specific recognition to cope with binding complexity that are critical for creating clinical viable tools to precisely modify the human genome. Our findings indicate preservation of general modularity and significant alteration of the rank-specific binding preferences of the three-finger binding domain of transcription factor SP1 when exchanging amino acids in the 2nd finger.


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