Arya Preeti, Acharya Vishal
Functional Genomics and Complex System Lab, Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Council of Scientific and Industrial Research, Palampur- 176061, Himachal Pradesh, India.
Academy of Scientific and Innovative Research (AcSIR), CSIR-Institute of Himalayan Bioresource Technology (CSIR-IHBT) Campus, Palampur, Himachal Pradesh, India.
PLoS One. 2016 Mar 1;11(3):e0150634. doi: 10.1371/journal.pone.0150634. eCollection 2016.
NACHT NTPases and AP-ATPases belongs to STAND (signal transduction ATPases with numerous domain) P-loop NTPase class, which are known to be involved in defense signaling pathways and apoptosis regulation. The AP-ATPases (also known as NB-ARC) and NACHT NTPases are widely spread throughout all kingdoms of life except in plants, where only AP-ATPases have been extensively studied in the scenario of plant defense response against pathogen invasion and in hypersensitive response (HR). In the present study, we have employed a genome-wide survey (using stringent computational analysis) of 67 diverse organisms viz., archaebacteria, cyanobacteria, fungi, animalia and plantae to revisit the evolutionary history of these two STAND P-loop NTPases. This analysis divulged the presence of NACHT NTPases in the early green plants (green algae and the lycophyte) which had not been previously reported. These NACHT NTPases were known to be involved in diverse functional activities such as transcription regulation in addition to the defense signaling cascades depending on the domain association. In Chalmydomonas reinhardtii, a green algae, WD40 repeats found to be at the carboxyl-terminus of NACHT NTPases suggest probable role in apoptosis regulation. Moreover, the genome of Selaginella moellendorffii, an extant lycophyte, intriguingly shows the considerable number of both AP-ATPases and NACHT NTPases in contrast to a large repertoire of AP-ATPases in plants and emerge as an important node in the evolutionary tree of life. The large complement of AP-ATPases overtakes the function of NACHT NTPases and plausible reason behind the absence of the later in the plant lineages. The presence of NACHT NTPases in the early green plants and phyletic patterns results from this study raises a quandary for the distribution of this STAND P-loop NTPase with the apparent horizontal gene transfer from cyanobacteria.
NACHT NTP酶和AP-ATP酶属于STAND（具有多个结构域的信号转导ATP酶）P环NTP酶类别，已知它们参与防御信号通路和细胞凋亡调控。AP-ATP酶（也称为NB-ARC）和NACHT NTP酶广泛分布于除植物以外的所有生物界，在植物中，仅对AP-ATP酶在植物防御病原体入侵反应和超敏反应（HR）中的情况进行了广泛研究。在本研究中，我们对67种不同的生物（即古细菌、蓝细菌、真菌、动物和植物）进行了全基因组调查（使用严格的计算分析），以重新审视这两种STAND P环NTP酶的进化历史。该分析揭示了早期绿色植物（绿藻和石松）中存在NACHT NTP酶，这在以前未曾报道过。这些NACHT NTP酶除了参与防御信号级联反应外，还根据结构域关联参与多种功能活动，如转录调控。在绿藻莱茵衣藻中，发现NACHT NTP酶的羧基末端存在WD40重复序列，这表明其在细胞凋亡调控中可能发挥作用。此外，现存石松小立碗藓的基因组有趣地显示，与植物中大量的AP-ATP酶相比，AP-ATP酶和NACHT NTP酶的数量都相当可观，并成为生命进化树中的一个重要节点。大量的AP-ATP酶取代了NACHT NTP酶的功能，这可能是后者在植物谱系中缺失的合理原因。本研究中早期绿色植物中NACHT NTP酶的存在及其系统发育模式，引发了关于这种STAND P环NTP酶分布的难题，以及其明显的来自蓝细菌的水平基因转移。
