Fig. 1. Expression of B-class Eph receptors and ephrins in the adult mouse kidney. (A,B) Amplification of ephrin-B and EphB mRNAs by RT-PCR. (A) Substantial levels of endogenous ephrin-B1, EphB2 and EphB6 are amplified from adult mouse kidney. Bands were not detected in controls in which the RT reaction was omitted (not shown). (B) Amplification of ephrin-B1, EphB2 and EphB6 from the cortex and the medulla of the kidney. (C) Densitometric quantification of the amplification levels of ephrin-B1, EphB2 and EphB6 mRNA in the cortex and medulla of the kidney. Data from three independent experiments, normalized to the levels of the GAPDH amplification products, are shown as mean ± s.d. Comparisons were performed using unpaired t-test. EphB2 expression in the medulla is significantly higher than in the cortex (P=0.002), whereas expression levels of ephrin-B1 and EphB6 are not significantly different between the two (P=0.407 and 0.692, respectively). (D) EphB2 tyrosine phosphorylation in adult mouse kidney. Lysates from the whole kidney were immunoprecipitated with anti-EphB2 antibodies. Immunoprecipitates were separated by SDS-PAGE and probed by immunoblotting with antibodies as indicated at the right.