■截短的血红蛋白2参与磷剥夺过程中PSR1调节的基因表达的微调。截短的血红蛋白形成了一个在生活的所有领域中发现的大家庭。然而,这些蛋白质的大多数生理功能仍有待阐明。在藻类莱茵衣藻模型中,已知大量营养剥夺会升高截短的血红蛋白2(THB2)。这项研究调查了THB2在P缺乏细胞中磷(P)限制反应基因子集的调控中的作用。在amiTHB2菌株中THB2的表达降低导致一组P剥夺诱导的基因下调,这些基因编码具有不同亚细胞位置和功能的蛋白质(例如,PHOX,LHCSR3.1、LHCSR3.2、PTB2和PTB5)。此外,我们的结果提供了主要证据,即可溶性鸟苷酸环化酶12基因(CYG12)是P剥夺调节的组成部分。此外,在P限制下,适应过程中最关键的调节因子PSR1基因的转录被一氧化氮(NO)抑制。总的来说,结果表明,THB2控制的NO水平与PSR1依赖性诱导几个P剥夺反应基因之间存在紧密的调控联系,这些基因在P限制期间在细胞中具有各种作用。
UNASSIGNED: Truncated hemoglobin 2 is involved in fine-tuning of PSR1-regulated gene expression during phosphorus deprivation. Truncated hemoglobins form a large family found in all domains of life. However, a majority of physiological functions of these proteins remain to be elucidated. In the model alga Chlamydomonas reinhardtii, macro-nutritional deprivation is known to elevate truncated hemoglobin 2 (THB2). This study investigated the role of THB2 in the regulation of a subset of phosphorus (P) limitation-responsive genes in cells suffering from P-deficiency. Underexpression of THB2 in amiTHB2 strains resulted in downregulation of a suite of P deprivation-induced genes encoding proteins with different subcellular location and functions (e.g., PHOX, LHCSR3.1, LHCSR3.2, PTB2, and PTB5). Moreover, our results provided primary evidence that the soluble guanylate cyclase 12 gene (CYG12) is a component of the P deprivation regulation. Furthermore, the transcription of PSR1 gene for the most critical regulator in the acclimation process under P restriction was repressed by nitric oxide (NO). Collectively, the results indicated a tight regulatory link between the THB2-controlled NO levels and PSR1-dependent induction of several P deprivation responsive genes with various roles in cells during P-limitation.