arg7 (SPBC1773.14) encodes an argininosuccinate lyase (EC 4.3.2.1) of fission yeast, a lyase-1 family enzyme orthologous to S. cerevisiae ARG4 and human ASL. It cleaves argininosuccinate to L-arginine and fumarate in the cytosol, the last step of arginine biosynthesis. S. pombe has a second argininosuccinate lyase, arg41 (SPBC1539.03c); in a genome-wide deletion screen the arg41 deletion, but not the arg7 deletion, caused arginine auxotrophy, so the two paralogs may differ in their in vivo contribution. Note that S. pombe arg7 is unrelated to S. cerevisiae ARG7 (ornithine acetyltransferase, S. pombe aga1).
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0000050 urea cycle | IC GO_REF:0000111 | KEEP AS NON CORE | Summary: This enzyme performs a shared ornithine-to-arginine reaction within the fungal arginine/urea reaction network. Reason: Live GO:0000050 defines ornithine-to-arginine synthesis followed by arginine cleavage to urea and regenerated ornithine; it does not require a ureotelic organism or nitrogen excretion. The target has the annotated OTC/ASS/ASL reaction and native fungal arginase supplies the return chemistry. Retain the existing process annotation as a contextual role, without asserting measured net full-cycle flux or a metazoan detoxification function. The primary role remains arginine biosynthesis. PMID:20435771 directly measures S. pombe Car1/Car3 arginase activity and urea production. Supporting Evidence: PMID:20435771 arginase catalyzes the degradation of arginine into urea and ornithine. file:SCHPO/arg7/arg7-uniprot.txt Reaction=2-(N(omega)-L-arginino)succinate = fumarate + L-arginine; file:SCHPO/arg7/arg7-uniprot.txt PATHWAY: Amino-acid biosynthesis; L-arginine biosynthesis; L-arginine |
| GO:0000050 urea cycle | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: This enzyme performs a shared ornithine-to-arginine reaction within the fungal arginine/urea reaction network. Reason: Live GO:0000050 defines ornithine-to-arginine synthesis followed by arginine cleavage to urea and regenerated ornithine; it does not require a ureotelic organism or nitrogen excretion. The target has the annotated OTC/ASS/ASL reaction and native fungal arginase supplies the return chemistry. Retain the existing process annotation as a contextual role, without asserting measured net full-cycle flux or a metazoan detoxification function. The primary role remains arginine biosynthesis. PMID:20435771 directly measures S. pombe Car1/Car3 arginase activity and urea production. Supporting Evidence: PMID:20435771 arginase catalyzes the degradation of arginine into urea and ornithine. file:SCHPO/arg7/arg7-uniprot.txt PATHWAY: Amino-acid biosynthesis; L-arginine biosynthesis; L-arginine |
| GO:0003824 catalytic activity | IEA GO_REF:0000002 | MODIFY | Summary: InterPro2GO mapping from IPR008948 (L-aspartase-like) and IPR020557 (fumarate lyase signature) to the root term catalytic activity. Reason: True but uninformative; the specific activity is argininosuccinate lyase. Proposed replacements: argininosuccinate lyase activity Supporting Evidence: file:SCHPO/arg7/arg7-uniprot.txt Reaction=2-(N(omega)-L-arginino)succinate = fumarate + L-arginine; |
| GO:0004056 argininosuccinate lyase activity | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA for argininosuccinate lyase activity at node PTN000154674 (sources include S. cerevisiae ARG4, E. coli ArgH, human ASL and arg7 itself). Reason: Correct inherited activity; arg7 among its own sources reflects its experimental annotation. Supporting Evidence: file:SCHPO/arg7/arg7-uniprot.txt Reaction=2-(N(omega)-L-arginino)succinate = fumarate + L-arginine; |
| GO:0004056 argininosuccinate lyase activity | IEA GO_REF:0000120 | ACCEPT | Summary: Combined IEA from ARBA00087497, InterPro IPR009049 (argininosuccinate lyase), Rhea 24020 and EC 4.3.2.1. Reason: Correct activity. Supporting Evidence: file:SCHPO/arg7/arg7-uniprot.txt Reaction=2-(N(omega)-L-arginino)succinate = fumarate + L-arginine; |
| GO:0004056 argininosuccinate lyase activity | IMP PMID:1868575 Sequence analysis of the ARG7 gene of Schizosaccharomyces po... | ACCEPT | Summary: PomBase IMP from Loppes et al. 1991, who sequenced S. pombe ARG7 (argininosuccinate lyase) and expressed it in S. cerevisiae; a C-terminal deletion retained some biological activity. Reason: Abstract-only paper; the curator read the full text. The gene-enzyme assignment is supported by heterologous expression and by the conserved lyase-1 active site. The 2020 screen result is condition-specific and does not invalidate the earlier functional expression/complementation evidence. Supporting Evidence: PMID:1868575 The complete nucleotide sequence of the ARG7 gene, coding for argininosuccinate PMID:1868575 lyase (EC 4.3.2.1), in the fission yeast (Schizosaccharomyces pombe) has been PMID:1868575 Additionally, a deletion removing 66 |
| GO:0005829 cytosol | HDA PMID:16823372 ORFeome cloning and global analysis of protein localization ... | ACCEPT | Summary: ORFeome-wide YFP localisation screen places arg7 in the cytosol. Reason: Consistent with the cytosolic location of the last two arginine biosynthetic steps in fungi. Supporting Evidence: PMID:16823372 we determined the localization of 4,431 proteins |
| GO:0005829 cytosol | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA for cytosol at node PTN000154674 (source S. cerevisiae ARG4). Reason: Fungal ASL is soluble/cytosolic; consistent with the ORFeome observation and the PomBase GO-CAM. Supporting Evidence: PMID:16823372 we determined the localization of 4,431 proteins |
| GO:0006526 L-arginine biosynthetic process | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA for L-arginine biosynthetic process at node PTN000154674 (sources include arg7, arg41, S. cerevisiae ARG4, mouse Asl and Aspergillus ArgB). Reason: Correct core process. Supporting Evidence: file:SCHPO/arg7/arg7-uniprot.txt PATHWAY: Amino-acid biosynthesis; L-arginine biosynthesis; L-arginine |
| GO:0006526 L-arginine biosynthetic process | IEA GO_REF:0000120 | ACCEPT | Summary: Combined IEA from ARBA00026424, InterPro IPR009049 and UniPathway UPA00068. Reason: Correct core process. Supporting Evidence: file:SCHPO/arg7/arg7-uniprot.txt PATHWAY: Amino-acid biosynthesis; L-arginine biosynthesis; L-arginine |
| GO:0006526 L-arginine biosynthetic process | IMP PMID:1868575 Sequence analysis of the ARG7 gene of Schizosaccharomyces po... | ACCEPT | Summary: PomBase IMP for arginine biosynthesis from Loppes et al. 1991 (ARG7 locus encoding ASL). Reason: Defer to the curator, who read the full text; ASL is the terminal arginine biosynthetic enzyme. Note that the 2020 deletion screen did not recover arg7 as an auxotroph (arg41 was), so the relative contribution of the two paralogs is unresolved. The 2020 screen result is condition-specific and does not invalidate the earlier functional expression/complementation evidence. Supporting Evidence: PMID:1868575 The complete nucleotide sequence of the ARG7 gene, coding for argininosuccinate PMID:32896087 arg7 is one of two argininosuccinate lyases (with deletion of the other one, arg41, showing arginine auxotrophy) |
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Download this section (compressed HTML)Q: Why is the arg41 deletion an arginine auxotroph while the arg7 deletion is not, given that arg7 was originally defined as an arginine-requiring locus? Is the deletion-library arg7 strain correct, or is arg41 the main argininosuccinate lyase in vivo?
Experiment: Measure argininosuccinate lyase activity and arginine prototrophy in freshly constructed arg7 and arg41 single and double deletions, and compare expression levels of the two paralogs.
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