PMC:3475487 / 14074-16803
Annnotations
{"target":"https://pubannotation.org/docs/sourcedb/PMC/sourceid/3475487","sourcedb":"PMC","sourceid":"3475487","source_url":"https://www.ncbi.nlm.nih.gov/pmc/3475487","text":"Discussion\nA BLAST search of C. parvum CysQ (cgd2_1810) protein shows the highest similarity with those of proteobacteria. Although it implies HGT from bacteria to this eukaryote, sequence similarity alone is not enough as its basis for several known reasons [27].\nIn addition, a phylogenetic analysis should support it. For this, initially, we relied on the tree built by PhylomeDB. However, its species coverage was biased or undersampled. On the other hand, CDD of NCBI is well subdivided into kingdom and function groups. C. parvum CysQ protein was mapped into the subfamily of IMPase, which is a bacterial CysQ domain, and comprises only bacterial sequences. Furthermore, C. parvum was located near Gamma- and Alphaproteobacteria in the CDTree. Hence, it seems that these results demonstrate that gene transfer events occurred from bacteria to C. parvum in the evolutionary process.\nOn the KEGG pathway, we raise the possibility that Alveolates, Euglenozoa, and Diplomonads of protozoa suffered from the losses of genes in the sulfate assimilation pathway. But, did C. parvum recover CysQ protein by HGT in the process of evolution? Sulfate assimilation shows highly conserved orthologs for each taxonomy lineage, and it plays important roles in sulfur metabolism, whereas Alveolates of protozoa, including Cryptosporidium, rarely have orthologous genes. For the pathogenic bacterium M. tuberculosis, sulfur-containing metabolites are essential to its pathogenesis and persistence in the host [18, 28], and the Database of Essential Genes (DEG) lists that Rv1286 (cysN) and Rv1285 (cysD), not Rv2131c (cysQ), are essential genes in sulfur metabolism of M. tuberculosis [29, 30]. Parasitic protozoa have diverse sulfur-containing amino acid metabolism that are considered to affect virulence and several stress response. On the other hand, C. parvum and Plasmodium falciparum lack a sulfur assimilation pathway, which is expected to be substituted from host cells [31].\nIn conclusion, although the sulfate assimilation pathway is missing in some protest lineages, C. parvum has a protein that is predicted as CysQ and has sequence similarity with that of proteobacteria, gram-negative bacteria. Moreover, the phylogenetic analysis supports the acquisition of cgd2_1810 from proteobacteria through horizontal gene transfer. Therefore, we can infer that C. parvum lost its genes in the sulfate assimilation pathway, including cysQ, during a parasitic way of life, and it acquired a copy of cysQ from bacteria by horizontal gene transfer. What is the biological role of this gene product? As the sole member, without other members, of the pathway, it can not assume the right role of CysQ. Its function is elusive at the moment.","divisions":[{"label":"Title","span":{"begin":0,"end":10}}],"tracks":[{"project":"2_test","denotations":[{"id":"23105923-11443357-44845621","span":{"begin":260,"end":262},"obj":"11443357"},{"id":"23105923-18454554-44845622","span":{"begin":1499,"end":1501},"obj":"18454554"},{"id":"23105923-21811406-44845623","span":{"begin":1503,"end":1505},"obj":"21811406"},{"id":"23105923-12657046-44845624","span":{"begin":1675,"end":1677},"obj":"12657046"},{"id":"23105923-18974178-44845625","span":{"begin":1679,"end":1681},"obj":"18974178"},{"id":"23105923-16230102-44845626","span":{"begin":1969,"end":1971},"obj":"16230102"}],"attributes":[{"subj":"23105923-11443357-44845621","pred":"source","obj":"2_test"},{"subj":"23105923-18454554-44845622","pred":"source","obj":"2_test"},{"subj":"23105923-21811406-44845623","pred":"source","obj":"2_test"},{"subj":"23105923-12657046-44845624","pred":"source","obj":"2_test"},{"subj":"23105923-18974178-44845625","pred":"source","obj":"2_test"},{"subj":"23105923-16230102-44845626","pred":"source","obj":"2_test"}]}],"config":{"attribute types":[{"pred":"source","value type":"selection","values":[{"id":"2_test","color":"#93eccd","default":true}]}]}}