The transcriptional factor YB-1 positively regulates Hsc70 transcription in Crassostrea hongkongensis

Highlights: • ChYB-1 shows affinity to ChHsc70 promoter in Crassostrea hongkongensis. • ChYB-1 positively regulates ChHsc70 transcription. • ChHsc70 and ChYB-1 transcriptions were coordinately induced by various stresses. • ChYB-1 transcription tends to be more persistently induced by pollutants. • This is the first report regarding positive regulator in controlling Hsc70 transcription. A Y-box binding protein ChYB-1 was discovered as a ChHsc70 promoter-associated protein in Crassostrea hongkongensis by DNA-affinity purification and mass spectrometry analysis. The overexpression of ChYB-1 in heterologous HEK293T cells led to clear enhancement of ChHsc70 promoter expression, while ChYB-1 depletion correlated with significant reduction of ChHsc70 transcription in the hemocytes of C. hongkongensis. Quantitative Real-time PCR analysis revealed that both ChHsc70 and ChYB-1 were transcriptionally responsive to external chemical or physical stressors. This indicates a plausible correlation between ChHsc70 and ChYB-1 in the genetic regulatory pathway triggered by external stresses. This study presents the first evidence of positive regulator for Hsc70 transcription and contributes to a better understanding of the regulatory mechanisms governing Hsc70 expression.