FIGURE 1.

Detection of isoform1 in insulin-producing cells. A, schematic representation of protein and exon structures of human CDKAL1 isoform1 and 2. The transcript coding isoform 2 lacks exons 4 and 13, and its translation starts from an internal ATG codon in a different reading frame than isoform 1. The different N-terminal portion in the two isoforms is highlighted either in light or dark gray. B, RT-PCR products amplified from INS-1 cells and human islet RNA with primers specific for rat and human CDKAL1 (lanes 3 and 6, respectively). For negative control reactions, no reverse transcriptase was added to the samples in lanes 1 and 4; no PCR primers were added to the samples in lanes 2 and 5. C, in vitro transcription and translation of rat CDKAL1 cDNA subcloned into pCRII. Reactions ± cDNA were subsequently analyzed by SDS-PAGE and immunoblot with anti-CDKAL1#2. The specific band corresponding to translated CDKAL1 is marked with *. A 55-kDa-reactive protein recognized by the same antibody is marked with ●.