Northern analysis: 2 μg poly(A⁺) RNA from various adult mouse tissues was loaded in each lane. A 1.3-kb fragment from the 5′ end of ship cDNA was used as probe. The membrane was reprobed with mouse actin probe to measure the amount of RNA in each lane. The same result was obtained with a 1.5-kb probe from the 3′-end of the ship cDNA clone.