The pattern of Kalrn promoter usage differs in NAc and prefrontal cortex; the C-promoter accounts for most of the full-length transcripts in the NAc while the B- and C-promoters contribute equally in the prefrontal cortex. The rat Kalrn A promoter was the first one identified and came from a cDNA library prepared from P21 rat hippocampus and cortex following electroconvulsive shock [11]. Subsequent studies demonstrated that the Kalrn A promoter is a minor contributor in the adult rat, mouse and human tissues examined [27,28]. The Kalrn D promoter is also a minor contributor in adult brain, but is the dominant Kalrn promoter in the pituitary (not shown). The Duet promoter, which produces transcripts that lack all of Kal7, is rarely used in the rat or human brain [28] and was not examined in this study. Interestingly, the intron sizes shown for mouse in Figure 1 are virtually identical to those reported for rat and human [28].
