Transcription Factors

Retinoic acid (RA; active metabolite of vitamin A) plays a prominent role in regulating the transition of proliferating precursor cells (such as carcinoma cells and neuronal precursors) to postmitotic differentiated cells. The retinoid X receptors (RXRs) family (RXRα, β and γ), preferentially bind 9-cis-RA and regulate gene transcription by forming heterodimers with a second family of RA receptors. RAs have been suggested to potentially play a therapeutic role in cervical cancer.

The retinoic acid receptor beta (RAR-beta) is a receptor for retinoic acid. This metabolite has profound effects on vertebrate development. Retinoic acid is a morphogen and powerful teratogen. RAR-beta controls cell function by directly regulating gene expression.

PROX1 (Prospero-related homeobox 1) is a divergent homeogene that regulates cell proliferation, fate determination and differentiation during vertebrate embryonic development. The protein is expressed in the developing lens and is also detected in embryonic brain, lung, liver and kidney; while in adult it is more abundant in heart and liver than in brain, skeletal muscle, kidney and pancreas. PROX1 is thought to play a fundamental role in early development of the CNS and may regulate gene expression and development of postmitotic undifferentiated young neurons.

Olig genes have been identified as the earliest known markers of oligodendrocyte lineage determination to date. Olig1 is a transcription factor which promotes formation and maturation of oligodendrocytes, especially within the brain. It is expressed in the ventral spinal cord as early as 9.5 dpc and by 15.5 dpc, olig1 is dispersed throughout the gray matter. In the postnatal brain, olig1 is present preferentially in the white matter, such as corpus callosum and cerebellar medulla. Olig1 has been demonstrated as necessary in the repair of brain lesions in patients with multiple sclerosis.

Cofactor of BRCA1 (negative elongation factor B, NELF-B, COBRA1) is an essential component of the NELF complex, a complex that negatively regulates the elongation of transcription by RNA polymerase II. The NELF complex, which acts via an association with the DSIF complex and causes transcriptional pausing, is counteracted by the P-TEFb kinase complex. COBRA1 can induce chromatin unfolding.