Expression of Annexin A7. (A) Northern blot analysis of RNA from ES-cells and embryos E7, E11, E15, E17 probed with a full length annexin A7 cDNA. Transcripts of 1.8 and 2.4 kb are detected in all stages examined (upper panel). Reprobing with a β-actin probe verified equal loading (lower panel, 2.0 kb band). (B) Murine ES cells (ES) express only the small Annexin A7 isoform. Both isoforms are expressed in neuroblastoma neuro-2a cells (N2A), heart (HRT) and brain tissue (CNS) from adult mice. Proteins from neuro-2a and ES cells, heart and brain were resolved by SDS polyacrylamide gel electrophoresis (12% acrylamide) and transferred to nitrocellulose membranes. The Western blot was probed with mAb 203–217 followed by incubation with a peroxidase coupled secondary antibody. Detection was with enhanced chemiluminescence.