Disease relevance of SPS1

• Heterologous expression of either SPS1 or SPS2 allowed the generation of UQ-9 in a decaprenyl diphosphate synthase-defective strain of fission yeast and also in wild-type Escherichia coli [1].

High impact information on SPS1

• The catalytic domain of Sps1 is 44% identical to the kinase domain of yeast Ste20, a protein involved in the pheromone-induced signal transduction pathway [2].
• Cells of a MATa/MAT alpha sps1/sps1 strain arrest after meiosis and fail to activate genes that are normally expressed at a late time of sporulation [2].
• Despite their inability to complete spore formation, sps1-arrested cells are able to resume mitotic growth on transfer to rich medium, generating haploid progeny [2].
• 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) [3].
• Sum1 and Hst1 repress middle sporulation-specific gene expression during mitosis in Saccharomyces cerevisiae [4].

Biological context of SPS1

• Deletion of SPS1 impinges on the formation of the spore wall, which surrounds each of the haploid nuclei generated by the meiotic divisions [5].
• SWM1 is expressed at low levels during vegetative growth but its transcription is strongly induced under sporulating conditions, with kinetics similar to those of middle sporulation-specific genes [6].
• All of the phenotypes observed are similar to those found for the deletion of SPS1 or SMK1, two putative components of a sporulation-specific MAP kinase cascade [6].
• The 3' end of the transcript encoded by the SPS1 gene was found to map only 185 base pairs from the 5' end of the SPS2 gene [7].
• A diploid MATa/MAT alpha strain homozygous for a disruption of the SPS1 gene failed to form asci when subjected to sporulation conditions [7].

Anatomical context of SPS1

• Here, we demonstrate that the new internal membranes that surround the meiotic nuclei appear normal in the absence of Sps1p [5].

Associations of SPS1 with chemical compounds

• These two different subcellular localizations are thought to be the reflection of their roles in solanesyl diphosphate synthesis in two different parts: presumably SPS1 and SPS2 for the side chains of ubiquinone and plastoquinone, respectively [1].

Co-localisations of SPS1

• Sps1p colocalized with Chs3p to peripheral and internal punctate structures and prospore membranes [5].

Regulatory relationships of SPS1

• 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 [8].
• SMK1 encodes a mitogen-activated protein kinase required for spore morphogenesis that is expressed as a middle sporulation-specific gene [9].
• We propose that the IME1 and IME2 products can each activate sporulation-specific genes independently [10].
• NDT80 and the meiotic recombination checkpoint regulate expression of middle sporulation-specific genes in Saccharomyces cerevisiae [11].

Other interactions of SPS1

• However, epistasis analyses indicate that Swm1p does not form part of the Sps1p-Smk1p-MAP kinase pathway [6].
• Deletion of SWM1 specifically affects the expression of mid-late and late sporulation-specific genes [6].
• We report here that IME1 is essential for expression of four sporulation-specific genes [10].
• We also found that mutants lacking CAK1 are blocked early in meiotic development, as they show substantial delays in premeiotic DNA synthesis and defects in the expression of sporulation-specific genes, including IME1 [12].
• RSC1 and RSC2 are required for expression of mid-late sporulation-specific genes in Saccharomyces cerevisiae [13].

Analytical, diagnostic and therapeutic context of SPS1

• 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 [14].
• H4 S1ph may promote chromatin compaction, since deletion of SPS1 increases accessibility to antibody immunoprecipitation; furthermore, either deletion of Sps1 or an H4 S1A substitution results in increased DNA volume in nuclei within spores [15].

References