Simultaneous deletion of and enhancers in the retina alters photoreceptor and bipolar cell fate specification, yet differs from deleting both genes.

The transcription factor OTX2 is required for photoreceptor and bipolar cell formation in the retina. It directly activates the transcription factors and through cell type-specific enhancers. PRDM1 and VSX2 work in opposition, such that PRDM1 promotes photoreceptor fate and VSX2 bipolar cell fate.

Challenges for health plans in influenza immunization.

Balancing the interests of patients and physicians is one of many challenges health plans experience. Although it is clear that influenza vaccination is an important part of any wellness program, the question of who should pay for it remains an important issue.