Transcriptome analysis of the anhydrobiotic cell line Pv11 infers the mechanism of desiccation tolerance and recovery

Abstract

The larvae of the African midge, Polypedilum vanderplanki, can enter an ametabolic state called anhydrobiosis to overcome fatal desiccation stress. The Pv11 cell line, derived from P. vanderplanki embryo, shows desiccation tolerance when treated with trehalose before desiccation and resumes proliferation after rehydration. However, the molecular mechanisms of this desiccation tolerance remain unknown. Here, we performed high-throughput CAGE-seq of mRNA and a differentially expressed gene analysis in trehalose-treated, desiccated, and rehydrated Pv11 cells, followed by gene ontology analysis of the identified differentially expressed genes. We detected differentially expressed genes after trehalose treatment involved in various stress responses, detoxification of harmful chemicals, and regulation of oxidoreduction that were upregulated. In the desiccation phase, L-isoaspartyl methyltransferase and heat shock proteins were upregulated and ribosomal proteins were downregulated. Analysis of differentially expressed genes during rehydration supported the notion that homologous recombination, nucleotide excision repair, and non-homologous recombination were involved in the recovery process. This study provides initial insights into the molecular mechanisms underlying the extreme desiccation tolerance of Pv11 cells.

Identification of a master transcription factor and a regulatory mechanism for desiccation tolerance in the anhydrobiotic cell line Pv11

“…LEA and PIMT proteins prevent protein denaturation caused by desiccation. The above genes are also upregulated in Pv11 cells after pretreatment with a high concentration of trehalose; thus, trehalose could play a role in the initiation of the transcription of anhydrobiosis-related genes [16]. Genes for oxygen-binding hemoglobins and aquaporins, which controls osmotic pressure on the phospholipid membrane, are upregulated [11,17].…”

“…Genes for oxygen-binding hemoglobins and aquaporins, which controls osmotic pressure on the phospholipid membrane, are upregulated [11,17]. The genes related to the ribosome complex are downregulated, reducing energy consumption for protein translation; in desiccated Pv11 cells, no significant changes in gene expression have been detected and the expression of each gene is steady [16]. The addition of water to dried Pv11 cells significantly upregulates the genes related to DNA repair, especially to homologous recombination and nucleotide excision repair [16,18].…”

“…The genes related to the ribosome complex are downregulated, reducing energy consumption for protein translation; in desiccated Pv11 cells, no significant changes in gene expression have been detected and the expression of each gene is steady [16]. The addition of water to dried Pv11 cells significantly upregulates the genes related to DNA repair, especially to homologous recombination and nucleotide excision repair [16,18]. These genes are needed not only to repair DNA damage that occurred during desiccation despite the activity of anhydrobiosis-related protective genes, but also to help resume proliferation.…”

“…Although various genes related to desiccation tolerance have been detected and molecular mechanisms for the anhydrobiosis of P. vanderplanki have been inferred [9][10][11][12][13][14][15][16][17][18], the transcription factors and regulatory mechanisms that drive the expression of these genes have not been clarified. Mazin et al revealed that heat shock factor (HSF) has a substantial role in regulation of these genes [19]; the HSF-binding element is enriched in the enhancers of anhydrobiosisrelated genes.…”

Cas9-mediated Genome Editing Reveals a Significant Contribution of Calcium Signaling Pathways to Anhydrobiosis in Pv11

“…During the pre-treatment, Pv11 cells uptake trehalose for the protection of biological molecules against forthcoming desiccation. In addition, trehalose treatment leads to changes in the gene expression profile 8,9 , suggesting that trehalose should be also a signal trigger for the gene expression, but exact mechanism of such interaction is unknown.…”