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 ChYB1 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. (C) 2017 Published by Elsevier Inc.