Disease relevance of pho

• Role of the transcription start site core region and transcription factor YY1 in Rous sarcoma virus long terminal repeat promoter activity [1].

High impact information on pho

• CtBP mutation does not result in YY1 degradation or transport from the nucleus, suggesting a mechanism whereby YY1 DNA binding ability is masked [2].
• We propose that PHO acts to anchor PcG protein complexes to DNA [3].
• YY1 functionally compensated for loss of PHO in pho mutant flies and partially corrected mutant phenotypes [4].
• Moreover, grainyhead interacts genetically with pleiohomeotic in a transgene-based, pairing-dependent silencing assay [5].
• PHO contacts the BRM complex through its zinc finger DNA-binding domain and a short N-terminal region [6].

Biological context of pho

• We examined the distribution of five PcG proteins on polytene chromosomes from pho-like, pho double mutants [7].
• The double mutant phenotypes were more severely affected by the pho maternal effect mutation than in zygotic mutant background, suggesting dosage-dependent processes [8].
• These results suggest that Pho and Pho-like act redundantly to repress homeotic genes [7].
• The Drosophila pleiohomeotic mutation enhances the Polycomblike and Polycomb mutant phenotypes during embryogenesis and in the adult [8].
• The Drosophila Polycomb group gene pleiohomeotic encodes a DNA binding protein with homology to the transcription factor YY1 [3].

Anatomical context of pho

• The absence of maternally supplied products from all of the genes studied except l(4)29 can be largely or completely compensated for by the activity in the zygote of a paternally contributed wild-type allele [9].

Associations of pho with chemical compounds

• Deletion of this short YY1 motif did not affect transient transcriptional repression but ablated PcG repression, PcG protein recruitment to DNA, and methylation of H3 lysine 27 [10].
• To test if these elements were functionally responsive to YY1, we performed transient expression experiments in Drosophila S-2 cells transfected with heterologous reporter gene constructs driven by histone H4 gene segments fused to the thymidine kinase promoter [11].

Physical interactions of pho

• Importantly, we found that the PC-binding domain of PHO can mediate transcriptional repression in transfected Drosophila Schneider cells [6].

Regulatory relationships of pho

• Pcl and Pc strongly enhanced pho phenotypes in the legs and tergite of the adult fly [8].

Other interactions of pho

• We characterize pho-like, a gene encoding a protein with high similarity to Pho [7].
• Finally, we found that YY1, as well as Polycomb, required the co-repressor protein CtBP for repression in vivo [4].
• It is argued that, with the exception of l(4)29, the genes studied in this report are qualitatively similar in function to the previously described BX-C regulators Pc, esc, and sxc [9].
• PHO and the GAF proteins bind to these sites in vitro [12].
• In an Ultrabithorax reporter gene, point mutations in these Pleiohomeotic binding sites abolish PcG repression in vivo [13].

Analytical, diagnostic and therapeutic context of pho

• With mobility shift assays and DNA pulldown experiments, we demonstrated that PHO is able to link PC, which lacks sequence-specific DNA-binding activity, to the DNA [6].

References