TEF (Thyrotrophic Embryonic Factor): TEF is a member of the PAR bZIP (proline and acidic amino acid-rich basic leucine zipper) transcription factor family. TEF plays a key role in regulating the circadian rhythm and controlling the expression of clock-dependent genes. It is essential for maintaining daily physiological cycles, including metabolism and hormone secretion. Dysregulation of TEF can affect circadian rhythm-related disorders and metabolic health, highlighting its importance in synchronising biological processes with the environmental light-dark cycle.