Figure 1.

Tissue-specific knockout of the frataxin gene in pancreatic β cells. (a) A genomic PCR derived from primers located up- and downstream of the putatively knocked-out exon 4 of the frataxin gene. DNA was isolated from indicated tissue from one 4-week-old lox control animal (first lane of each triplet) and two 4-week-old knockout animals (second and third lanes of each triplet). DNA from a whole-body knockout (Gen KO) was used as a positive control (9). (b) A reversely transcribed PCR using RNA from the same animals as in a, using primers located in exons 3 and 5 of the murine frataxin cDNA. (c) Subsets of microphotographs (original magnification, ×200) of immunohistochemistry against murine frataxin on islets from 4-week-old animals of the indicated genotype. (d) Microphotographs (original magnification, ×200) of one representative knockout islet immunohistochemically stained for glucagon (green, left) and frataxin (red, middle). Overlay of both microphotographs indicates colocalization of the remaining frataxin signals in knockout islets with glucagon-positive cells.