scholarly journals Drosophila Paired regulates late even-skipped expression through a composite binding site for the paired domain and the homeodomain

Development ◽  
1996 ◽  
Vol 122 (9) ◽  
pp. 2697-2707 ◽  
Author(s):  
M. Fujioka ◽  
P. Miskiewicz ◽  
L. Raj ◽  
A.A. Gulledge ◽  
M. Weir ◽  
...  

The even-skipped (eve) pair-rule gene plays a key role in the establishment of the anterior-posterior segmental pattern of the Drosophila embryo. The continuously changing pattern of eve expression can be resolved into two phases. Early expression consists of seven broad stripes in the blastoderm embryo, while late expression, which occurs after cellularization, consists of narrow stripes with sharp anterior borders that coincide with the odd-numbered parasegment boundaries. Previous studies have shown that these two phases are controlled by separate classes of cis elements in the eve promoter. Early stripes are expressed by multiple stripe-specific elements under the control of maternal-effect genes and gap genes, while late stripes are expressed by a single regulatory element, the ‘late element’, under the control of pair-rule genes including eve itself. We report here that paired (prd), a pair-rule gene which had been considered to be below eve in the regulatory hierarchy of pair-rule genes, in fact plays a critical role in the regulation of late eve expression. Transgenic analysis shows that this regulation is largely mediated by an evolutionarily conserved sequence within the late element termed PTE (Paired Target Element). In vitro analysis shows that the Prd protein binds strongly to this sequence. Interestingly, PTE contains juxtaposed binding sites for the two DNA-binding domains of the Prd protein, the paired domain and the homeodomain. Mutagenesis of either binding site leads to significant reduction in the activity of the late element, indicating that both DNA-binding domains in the Paired protein are required for regulation.

2020 ◽  
Author(s):  
Audrey Pelletier ◽  
Alexandre Mayran ◽  
Arthur Gouhier ◽  
James G Omichinski ◽  
Aurelio Balsalobre ◽  
...  

AbstractThe pioneer transcription factor Pax7 contains two DNA binding domains (DBD), a paired and a homeo domain. Previous work on Pax7 and the related Pax3 had shown that each DBD can bind a cognate DNA sequence, thus defining two targets of binding and possibly modalities of action. Genomic targets of Pax7 pioneer action leading to chromatin opening are enriched for composite DNA target sites containing juxtaposed binding sites for both paired and homeo domains. The present work investigated the implication of both DBDs in pioneer action. We now show that the composite sequence is a higher affinity Pax7 binding site compared to either paired or homeo binding sites and that efficient binding to this site involves both DBDs. We also show that a Pax7 monomer binds composite sites and that methylation of cytosines within the binding site does not affect binding, which is consistent with pioneer action exerted at methylated DNA sites within nucleosomal heterochromatin. Finally, introduction of single amino acid mutations in either the paired or homeo domain that impair binding to cognate DNA sequences showed that both DBDs must be intact for pioneer action. In contrast, only the paired domain is required for low affinity binding of heterochromatin sites. Thus, Pax7 pioneer action on heterochromatin requires unique protein:DNA interactions that are more complex compared to its simpler DNA binding modalities at accessible enhancer target sites.Significance StatementPioneer transcription factors have the unique ability to recognize DNA target sites within closed heterochromatin and to trigger chromatin opening. Only a fraction of the heterochromatin recruitment sites of pioneers are subject to chromatin opening. The molecular basis for this selectivity is unknown and the present work addressed the importance of DNA sequence affinity for selection of sites to open. The pioneering ability of the pioneer factor Pax7 is not strictly determined by affinity or DNA sequence of binding sites, nor by number or methylation status of DNA sites. Mutation analyses showed that recruitment to heterochromatin is primarily dependent on the Pax7 paired domain whereas the ability to open chromatin requires both paired and homeo DNA binding domains.


Development ◽  
1996 ◽  
Vol 122 (9) ◽  
pp. 2673-2685 ◽  
Author(s):  
C. Bertuccioli ◽  
L. Fasano ◽  
S. Jun ◽  
S. Wang ◽  
G. Sheng ◽  
...  

The Drosophila pair-rule gene paired is required for the correct expression of the segment polarity genes wingless, engrailed and gooseberry. It encodes a protein containing three conserved motifs: a homeodomain (HD), a paired domain (PD) and a PRD (His/Pro) repeat. We use a rescue assay in which paired (or a mutated version of paired in which the functions of the conserved motifs have been altered) is expressed under the control of its own promoter, in the absence of endogenous paired, to dissect the Paired protein in vivo. We show that both the HD and the N- terminal subdomain of the PD (PAI domain) are absolutely required within the same molecule for normal paired function. In contrast, the conserved C-terminal subdomain of the PD (RED domain) appears to be dispensable. Furthermore, although a mutation abolishing the ability of the homeodomain to dimerize results in an impaired Paired molecule, this molecule is nonetheless able to mediate a high degree of rescue. Finally, a paired transgene lacking the PRD repeat is functionally impaired, but still able to rescue to viability. We conclude that, while Prd can use its DNA-binding domains combinatorially in order to achieve different DNA-binding specificities, its principal binding mode requires a cooperative interaction between the PAI domain and the homeodomain.


1993 ◽  
Vol 13 (12) ◽  
pp. 7257-7266 ◽  
Author(s):  
C Carriere ◽  
S Plaza ◽  
P Martin ◽  
B Quatannens ◽  
M Bailly ◽  
...  

After differential screening of a cDNA library constructed from quail neuroretina cells (QNR) infected with the v-myc-containing avian retrovirus MC29, we have isolated a cDNA clone, Pax-QNR, homologous to the murine Pax-6, which is mutated in the autosomal dominant mutation small eye of mice and in the disorder aniridia in humans. Here we report the characterization of the Pax-QNR proteins expressed in the avian neuroretina. From bacterially expressed Pax-QNR peptides, we obtained rabbit antisera directed against different domains of the protein: paired domain (serum 11), domain between the paired domain and homeodomain (serum 12), homeodomain (serum 13), and carboxyl-terminal part (serum 14). Sera 12, 13, and 14 were able to specifically recognize five proteins (48, 46, 43, 33, and 32 kDa) in the neuroretina. In contrast to proteins of 48, 46, and 43 kDa, proteins of 33 and 32 kDa were not recognized by the paired antiserum (serum 11). Paired-less and paired-containing proteins exhibited the same half-life (6 h) and were phosphorylated mostly on serine residues. Immunoprecipitations performed with subcellular fractions of neuroretinas showed that the paired-containing proteins were located in the nucleus, whereas the 33- and 32-kDa proteins were found essentially in the cytoplasmic compartment. However, immunofluorescence experiments performed after transient transfections showed that p46 and p33/32 were also located in vivo into the nucleus. Thus, the Pax-QNR/Pax-6 gene can produce proteins with two DNA-binding domains as well as proteins containing only the DNA-binding homeodomain.


2017 ◽  
Author(s):  
Liyang Zhang ◽  
Gabriella D. Martini ◽  
H. Tomas Rube ◽  
Judith F. Kribelbauer ◽  
Chaitanya Rastogi ◽  
...  

ABSTRACTThe DNA-binding interfaces of the androgen (AR) and glucocorticoid (GR) receptors are virtually identical, yet these transcription factors share only about a third of their genomic binding sites and regulate similarly distinct sets of target genes. To address this paradox, we determined the intrinsic specificities of the AR and GR DNA binding domains using a refined version of SELEX-seq. We developed an algorithm, SelexGLM, that quantifies binding specificity over a large (31 bp) binding-site by iteratively fitting a feature-based generalized linear model to SELEX probe counts. This analysis revealed that the DNA binding preferences of AR and GR homodimers differ significantly, both within and outside the 15bp core binding site. The relative preference between the two factors can be tuned over a wide range by changing the DNA sequence, with AR more sensitive to sequence changes than GR. The specificity of AR extends to the regions flanking the core 15bp site, where isothermal calorimetry measurements reveal that affinity is augmented by enthalpy-driven readout of poly-A sequences associated with narrowed minor groove width. We conclude that the increased specificity of AR is correlated with more enthalpy-driven binding than GR. The binding models help explain differences in AR and GR genomic binding, and provide a biophysical rationale for how promiscuous binding by GR allows functional substitution for AR in some castration-resistant prostate cancers.


1993 ◽  
Vol 13 (12) ◽  
pp. 7257-7266
Author(s):  
C Carriere ◽  
S Plaza ◽  
P Martin ◽  
B Quatannens ◽  
M Bailly ◽  
...  

After differential screening of a cDNA library constructed from quail neuroretina cells (QNR) infected with the v-myc-containing avian retrovirus MC29, we have isolated a cDNA clone, Pax-QNR, homologous to the murine Pax-6, which is mutated in the autosomal dominant mutation small eye of mice and in the disorder aniridia in humans. Here we report the characterization of the Pax-QNR proteins expressed in the avian neuroretina. From bacterially expressed Pax-QNR peptides, we obtained rabbit antisera directed against different domains of the protein: paired domain (serum 11), domain between the paired domain and homeodomain (serum 12), homeodomain (serum 13), and carboxyl-terminal part (serum 14). Sera 12, 13, and 14 were able to specifically recognize five proteins (48, 46, 43, 33, and 32 kDa) in the neuroretina. In contrast to proteins of 48, 46, and 43 kDa, proteins of 33 and 32 kDa were not recognized by the paired antiserum (serum 11). Paired-less and paired-containing proteins exhibited the same half-life (6 h) and were phosphorylated mostly on serine residues. Immunoprecipitations performed with subcellular fractions of neuroretinas showed that the paired-containing proteins were located in the nucleus, whereas the 33- and 32-kDa proteins were found essentially in the cytoplasmic compartment. However, immunofluorescence experiments performed after transient transfections showed that p46 and p33/32 were also located in vivo into the nucleus. Thus, the Pax-QNR/Pax-6 gene can produce proteins with two DNA-binding domains as well as proteins containing only the DNA-binding homeodomain.


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.


2002 ◽  
Vol 277 (51) ◽  
pp. 49488-49494 ◽  
Author(s):  
Rajnikant Mishra ◽  
Ivan P. Gorlov ◽  
Lian Y. Chao ◽  
Sanjaya Singh ◽  
Grady F. Saunders

PAX6 functions as a transcription factor and has two DNA-binding domains, a paired domain (PD) and a homeodomain (HD), joined by a glycine-rich linker and followed by a proline-serine-threonine-rich (PST) transactivation region at the C terminus. The mechanism of PAX6 function is not clearly understood, and few target genes in vertebrates have been identified. In this report we described the functional analyses of patient missense mutations from the paired domain region of PAX6 and a paireddomain-less isoform (PD-less) of Pax6 that lacks the paired domain and part of the glycine-rich linker. The PD-less was expressed in the brain, eyes, and pancreas of mouse. The level of expression of this isoform was relatively higher in brain. The mutation sites PAX6-L46R and -C52R were located in the PD of PAX6 on either end of the 5a-polypeptide insert of the alternatively spliced form of PAX6, PAX6-5a. Another PAX6 mutant V53L described in this report was adjacent to C52R. We created corresponding mutations in PAX6 and PAX6-5a, and evaluated their transcriptional activation and DNA binding properties. The PD mutants of PAX6 (L46R, C52R, and V53L) exhibited lower transactivation activities and variable DNA binding ability than wild-type PAX6 with PD DNA-binding consensus sequences. The mutated amino acids containing PAX6-5a isoforms showed unexpected transactivation properties with a reporter containing HD DNA-binding sequences. PAX6-5a-C52R, and -V53L showed lower transactivation activities, but PAX6-5a-L46R had greater transactivation ability than PAX6-5a. The PD-less isoform of Pax6 lost its transactivational ability but could bind to the HD DNA-binding sequences. Functional analysis of the PD-less isoform of Pax6 as well as findings related to missense mutations in the PD suggest that the PD of PAX6 is required for HD function.


2014 ◽  
Vol 289 (31) ◽  
pp. 21605-21616 ◽  
Author(s):  
Shuo Wang ◽  
Miles H. Linde ◽  
Manoj Munde ◽  
Victor D. Carvalho ◽  
W. David Wilson ◽  
...  

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