Disease relevance of NDT80

• To facilitate biochemical analysis of Ndt80, we have expressed the DNA binding domain in Escherichia coli and purified the recombinant protein with an affinity chromatography procedure [1].

High impact information on NDT80

• Furthermore, noncrossover and crossover recombination are regulated differently. ndt80 mutants arrest in meiosis with unresolved Holliday junction intermediates and very few crossovers, while noncrossover heteroduplex products are formed at normal levels and with normal timing [2].
• The transcription factor Ndt80 appeared to be important for induction of a large group of genes at the end of meiotic prophase [3].
• In accordance with a late role for Ime2, we observed an increase in its activity during M phase that depended on Cdc28 and Ndt80 [4].
• We find that Ndt80 functions at pachytene of yeast gametogenesis (sporulation) to activate transcription of a set of genes required for both meiotic division (e.g., B-type cyclins) and gamete formation (e.g., SPS1) [5].
• Transcription of the Ndt80-regulated gene CLB1 is mediated by the checkpoint gene RAD17 [5].

Biological context of NDT80

• The NDT80 gene product could be a component of the cell cycle regulatory machinery involved in the transition out of pachytene, a participant in an unknown aspect of meiosis sensed by a pachytene checkpoint, or a SPO11- and RAD50-independent component of meiotic chromosomes that is the target of cell cycle signaling [6].
• Cloning and molecular analysis reveal that the NDT80 gene maps on the right arm of chromosome VIII between EPT1 and a Phe-tRNA gene, encodes a 627-amino-acid protein which exhibits no significant homology to other known proteins, and is transcribed specifically during middle meiotic prophase [6].
• Triggering of this checkpoint prevents phosphorylation and accumulation of active Ndt80 [7].
• Ndt80 contributes to the highly regulated cascade of sequential gene expression that directs spore formation in Saccharomyces cerevisiae [7].
• Gametogenesis in yeast is regulated by a transcriptional cascade dependent on Ndt80 [5].

Anatomical context of NDT80

• The induction kinetics of P(PMP47) and P(DAS1) revealed that methanol induces the expression of peroxisome membrane protein Pmp47, earlier than the expression of matrix enzyme dihydroxyacetone synthase (Das1p), and that this information is contained in the promoter region of the respective gene [8].

Associations of NDT80 with chemical compounds

• Here, we report the crystal structure at 2.3 A resolution of the DNA-binding domain of Ndt80 experimentally phased by using the anomalous and isomorphous signal from a single ordered Se atom per molecule of 272-aa residues [9].
• Regulation and physiological role of the DAS1 gene, encoding dihydroxyacetone synthase, in the methylotrophic yeast Candida boidinii [10].
• These and other experiments (e.g., those to determine the expression of the gene and the growth ability of the das1Delta strain on media containing methylamine or choline as a nitrogen source) suggested that DAS1 is involved in assimilation rather than dissimilation or detoxification of formaldehyde in the cells [10].

Enzymatic interactions of NDT80

• In addition, we show that the Ndt80 DNA binding domain can be phosphorylated by the meiosis-specific protein kinase Ime2 in vitro, but contrary to our initial hypothesis this phosphorylation does not significantly affect the affinity of Ndt80 for its target DNA sequence [1].

Regulatory relationships of NDT80

• This suggests that Ime2 activates expression of NDT80 by eliminating Sum1-mediated repression [11].
• We propose that a decrease in the efficiency of Sum1-mediated repression as cells progress through the early events of the sporulation program allows the previously inactive Ime1 tethered at the URS1(NDT80) sites to promote a low level of expression of the NDT80 gene [11].
• In particular, we found that a truncated version of Ndt80 that lacked the last 110 residues was able to promote expression of some middle sporulation-specific genes, but could not direct spore formation [7].
• These data suggest that Sum1 levels are regulated by the checkpoint and that progression of the meiotic divisions and spore differentiation can be differentially controlled by competition of the Sum1 repressor and Ndt80 activator for occupancy at key middle promoters [12].
• The Saccharomyces cerevisiae transcription factor Ndt80 selectively binds a DNA consensus sequence (the middle sporulation element [MSE]) to activate gene expression after the successful completion of meiotic recombination [13].

Other interactions of NDT80

• These results suggest that progression through sporulation may be controlled by the regulated competition between the Sum1 repressor and Ndt80 activator at key MSEs [14].
• Mutation of IME2 prevents expression of NDT80 in sporulating cells [11].
• Activation of the checkpoint leads to inhibition of Ndt80 activity and to stabilization of Swe1 and Sum1 [15].
• Thus, middle genes are expressed only on completion of meiotic recombination and subsequent generation of an active form of Ndt80p [16].
• Activity of phosphoforms and truncated versions of Ndt80, a checkpoint-regulated sporulation-specific transcription factor of Saccharomyces cerevisiae [7].

Analytical, diagnostic and therapeutic context of NDT80

• In situ hybridization using chromosome-specific probes confirms that the chromosomes in ndt80 mutants are paired and attached to the SCs [17].
• We tested two separate libraries built by random ligation of a single type of activator site either for a well-characterized sporulation factor, Ndt80, or for a new sporulation-specific regulatory site that we identified and several neutral spacer elements [18].

References