A novel transgenic mouse for gene-targeting within cells that express corticotropin-releasing factor

Corticotropin-releasing factor (CRF) orchestrates the mammalian endocrine, autonomic, and behavioral stress response and has been implicated in the pathophysiology of illnesses ranging from irritable bowel syndrome to mood and anxiety disorders. CRF is produced and released from a variety of cell types, making it difficult to distinguish the specific role of CRF from other neurotransmitters with which it colocalizes. To clarify the basic biology of the CRF neuron, we must be able to manipulate selectively CRFergic cells. Here we describe a novel transgenic mouse using 3.0 kb of the CRF promoter to drive expression of Cre-recombinase (CRFp3.0Cre). Crossing CRFp3.0Cre with a fluorescent reporter strain results in Cre-dependent green fluorescent protein expression within CRF-producing cells. Thus, CRF cells can be identified for single-cell polymerase chain reaction and electrophysiological procedures. Furthermore, the CRFp3.0Cre transgenic can be combined with other available mouse strains containing a "floxed" gene of interest to allow unparalleled detailed analysis of the CRF system.