DSIF, which stands for "DRB sensitivity-inducing factor," is a term commonly used in the medical and biological fields. Some synonyms for DSIF include "SPT4/5," "SUPT4H1/SUPT5H," and "positive elongation factor b." These terms refer to the same molecule involved in the regulation of gene expression through controlling RNA transcription. DSIF plays a critical role in maintaining proper mRNA elongation and preventing premature transcription termination. Understanding the synonyms for DSIF is essential for researchers and scientists to communicate effectively and avoid confusion when discussing the complex molecular mechanisms involved in gene expression.