Figure 1.

Temporal expression of Jak1 kinase during zebrafish development. RT–PCR analysis was used to compare the levels of Jak1 mRNA to the housekeeping gene EF1 alpha. The mRNA abundance for Jak1 and EF1 alpha is shown as expression relative to the maximally observed value for that mRNA species from the developmental stages examined. Jak1 mRNA is of maternal origin and rapidly decreases at the beginning of MBT, whereas EF1 alpha mRNA levels increase at the beginning of zygotic gene expression. Hours of development indicate times postfertilization at 28°C.