An unexpected role for leucyl aminopeptidase in UV tolerance revealed by a genome-wide fitness assessment in a model cyanobacterium.
An unexpected role for leucyl aminopeptidase in UV tolerance revealed by a genome-wide fitness assessment in a model cyanobacterium.
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DOI：
10.1073/pnas.2211789119
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发表时间：
2022-11-08
影响因子：
11.1
通讯作者：
中科院分区：
文献类型：
--
作者：
蓝藻占全球初级生产力的 25%，并主导着大片海洋区域和土壤结皮。虽然它们依靠光进行光合作用，但它们同时暴露在紫外线辐射 (UVR) 下。紫外线引起的损害会降低光合速率，这表明之前对全球初级生产力的计算可能被高估了。尽管紫外线对浮游植物有强烈影响，但尚未进行全基因组适应性评估，以确定在环境相关紫外线剂量下对光合生物体的紫外线耐受性重要的基因。我们报告了蓝藻中对紫外线耐受性最关键的基因，以及保守的亮氨肽酶的功能，其破坏会导致在紫外线下失去适应性。紫外线辐射 (UVR) 对生活在地球表面或附近的生物体具有显着的生理影响，但光合生物在富含紫外线的环境中适应所需的全套基因仍然未知。本研究报告了对蓝细菌细长聚球藻 PCC 7942 模型中在环境相关 UVR 剂量下影响 UVR 耐受性的基因进行全基因组适应性评估。我们的结果强调了编码参与 DNA 修复、谷胱甘肽合成、光系统 II 组装和维护的蛋白质的特定基因的重要性，以及编码假设蛋白质和其他与 UVR 耐受性的经典方法没有明显联系的基因的重要性。编码亮氨肽酶 (LAP) 的基因被破坏会导致 UVR 特异性的健康水平下降最大。酶测定表明，LAP 对二肽半胱氨酰-甘氨酸具有很强的 pH 依赖性亲和力，表明其参与谷胱甘肽分解代谢，作为夜间胞质 pH 水平的函数。 LAP 基因在急性 UVR 暴露下的低差异表达表明，其相对重要性在转录依赖性筛选中会被忽视。随后的实验揭示了其他生物体 LAP 敲除中类似的 UVR 敏感性表型，表明 LAP 在 UVR 耐受性中的功能作用得以保留。
Cyanobacteria account for ∼25% of global primary production and dominate vast regions of the ocean, as well as soil crusts. While they rely upon light availability for photosynthesis, they are simultaneously exposed to UV radiation (UVR). Damage induced by UVR decreases photosynthetic rates, suggesting that previous calculations of global primary production may be overestimated. Despite the strong impact of UVR on phytoplankton, there has not yet been a genome-wide fitness assessment to identify genes that are important for UVR tolerance in a photosynthetic organism under environmentally relevant UVR dosages. We report genes that are most critical for UVR tolerance in a cyanobacterium and the function of a conserved leucyl aminopeptidase whose disruption results in loss of fitness under UVR. UV radiation (UVR) has significant physiological effects on organisms living at or near the Earth’s surface, yet the full suite of genes required for fitness of a photosynthetic organism in a UVR-rich environment remains unknown. This study reports a genome-wide fitness assessment of the genes that affect UVR tolerance under environmentally relevant UVR dosages in the model cyanobacterium Synechococcus elongatus PCC 7942. Our results highlight the importance of specific genes that encode proteins involved in DNA repair, glutathione synthesis, and the assembly and maintenance of photosystem II, as well as genes that encode hypothetical proteins and others without an obvious connection to canonical methods of UVR tolerance. Disruption of a gene that encodes a leucyl aminopeptidase (LAP) conferred the greatest UVR-specific decrease in fitness. Enzymatic assays demonstrated a strong pH-dependent affinity of the LAP for the dipeptide cysteinyl-glycine, suggesting an involvement in glutathione catabolism as a function of night-time cytosolic pH level. A low differential expression of the LAP gene under acute UVR exposure suggests that its relative importance would be overlooked in transcript-dependent screens. Subsequent experiments revealed a similar UVR-sensitivity phenotype in LAP knockouts of other organisms, indicating conservation of the functional role of LAPs in UVR tolerance.
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影响因子：
3.7
作者：
Engler, Carola;Kandzia, Romy;Marillonnet, Sylvestre
通讯作者：
Marillonnet, Sylvestre
影响因子：
4.5
作者：
Dupont, CL;Goepfert, TJ;Ahnerz, BA
通讯作者：
Ahnerz, BA
影响因子：
7.4
作者：
Dobakova, Marika;Sobotka, Roman;Komenda, Josef
通讯作者：
Komenda, Josef
影响因子：
56.9
作者：
CULLEN, JJ;NEALE, PJ;LESSER, MP
通讯作者：
LESSER, MP
DOI：
10.1111/j.2517-6161.1995.tb02031.x
发表时间：
1995-01-01
影响因子：
5.8
作者：
BENJAMINI, Y;HOCHBERG, Y
通讯作者：
HOCHBERG, Y