Figure 1.

Expression patterns of mouse CAP1 and CAP2. (A) Northern blot analysis of CAP1 and CAP2 expression in adult mouse tissues. CAP1 (left) is expressed in all tissues except in skeletal muscle. CAP2 (right) is expressed at high levels in heart, brain, skeletal muscle, and testis and is also found in very low levels in lung and liver. The three different RNA populations recognized by the CAP2 probe are most likely a consequence of alternative mRNA processing (see text for details). (B) In situ hybridization on a transversal section of E10.5 mouse embryo shows that CAP1 expression is widespread. (C) Adjacent section shows that CAP2 expression is restricted to heart and developing muscles. (D) Hybridization of an adjacent section with a control CAP1 sense probe does not give significant background. (E) CAP1 is widely expressed at E12.5. (F) CAP2 is restricted to developing striated muscles at E12.5. (G) Elevated CAP1 expression is detected in hippocampus at E18.5. (H) Highest levels of CAP2 in brain is detected in thalamus at E18.5. These expression patterns indicate that CAP1 plays role as a general isoform, whereas CAP2 is a striated muscle specific isoform during early development. c, cartilage; cx, cortex; drg, dorsal root ganglion; h, heart; hi, hippocampus; k; kidney; l, limb; m; muscle; my, myotome; sc, spinal cord; th, thalamus.