The DEAD-box RNA helicase eIF4A regulates plant development and interacts with the hnRNP LIF2L1 in Physcomitrella patens
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eIF4A is a RNA-stimulated ATPase and helicase. Besides its key role in regulating cap-dependent translation initiation in eukaryotes, it also performs specific functions in regulating cell cycle progression, plant growth and abiotic stress tolerance. Flowering plants encode three eIF4A paralogues, eIF4A1, eIF4A2 and eIF4A3 that share conserved sequence motifs but differ in functions. To date, however, no information is available on eIF4A in basal land plants. In this study we report that genome of the moss Physcomitrella patens encodes multiple eIF4A genes. The encoded proteins possess the highly conserved motifs characteristic of the DEAD box helicases. Spatial expression analysis shows these genes to be ubiquitously expressed in all tissue types with Pp3c6_1080V3.1 showing high expression in filamentous protonemata. Targeted deletion of conserved core motifs in Pp3c6_1080V3.1 slowed protonemata growth and resulted in dwarfing of leafy gametophores suggesting a role for Pp3c6_1080V3.1 in regulating cell division/elongation. Rapid and strong induction of Pp3c6_1080V3.1 under salt stress and slow recovery of knockout plants upon exposure to high salt further suggest Pp3c6_1080V3.1 to be involved in stress management in P. patens. Protein–protein interaction studies that show Pp3c6_1080V3.1 to interact with the Physcomitrella heterogenous ribonucleoprotein, LIF2L1, a transcriptional regulator of stress-responsive genes in Arabidopsis. The results presented in this study provide insight into evolutionary conserved functions of eIF4A and shed light on the novel link between eIF4A activities and stress mitigation pathways/RNA metabolic processes in P. patens.
KeywordsProtein translation RNA helicases ATPases Eukaryotic translation initiation LIF2
VT and VP acknowledge financial assistance from Guru Gobind Singh Indraprastha University.
VT, VP and VK conducted the experiments. MK, GM and SK conceptualised the work, acquired funds and resources. VT and MK wrote the manuscript. All authors read and approved the manuscript.
This study was funded by Council of Scientific and Industrial Research (CSIR), Government of India (Grant # 38(1380)/14/EMR-II).
Compliance with ethical standards
Conflict of interest
VT, VP, GM, VK, SK declares that they have no conflict of interest.
This article does not contain any studies with human participants or animals performed by any of the authors.
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