Expression of specific corneous beta proteins in the developing digits of the Japanese gecko (Gekko japonicus) reveals their role in the growth of adhesive setae.

Abstract

Geckos possess strong adhesion ability, even can climb on smooth surface. Previous studies have shown that the setae of geckos play a crucial role in their ability to climb on vertical walls. But the biological molecular mechanism of their adhesion ability remains unclear. In the present study, the expression patterns of corneous beta proteins (CBPs) genes related to claws, scales, and feathers development (named as ge-gprp-9, ge-gprp-10, ge-gprp-11, ge-gprp-12, ge-gprp-13, ge-gprp-14, ge-gprp-15, and ge-gprp-16 respectively) in the developing pad lamellae of different embryonic stages (stage 34, stage 36, stage 39, and stage 42) of the Japanese gecko Gekko japonicus were detected using fluorescence quantitative PCR approach. The results showed that there were significant up-regulated expression of CBPs mRNA at embryonic stage 39 with the embryonic continuous maturation and the highest expression level was detected at embryonic stage 39 or stage 42. Moreover, the expression levels of four CBPs genes ge-gprp-9, ge-gprp-10, ge-gprp-11, and ge-gprp-12 in the embryonic and adult development of gecko were detected by fluorescence in situ hybridization technique. The results from in situ hybridization detection revealed that the positive signals of these CBPs genes expression were the same in the developing pad lamellae of G. japonicus. The positive signals of eight CBPs genes were mainly found in the setae tissue, oberhautchen, and β layer, which suggests these CBPs genes are involved in the growth of setae.