Stage- and tissue-dependent regulation of LGR5 expression during development.

<p>(A) Zygotic transcription of LGR5 begins in late embryogenesis during development in <i>X. laevis</i>. Total RNA was isolated from whole animals from stage 1 (fertilized egg) to stage 66 (the end of metamorphosis) and analyzed by qRT-PCR. The LGR5 expression shown in (C) was normalized against rpl8 expression determined at the same time. (B, C) Organ-specific temporal regulation of LGR5 during natural metamorphosis in <i>X. laevis</i>. Total RNA was isolated from tail, limb, and intestine of tadpoles at the indicated developmental stages and used for regular RT-PCR (B) or qRT-PCR (C) analysis of the LGR5 expression. In each RT-PCR, a primer set for the ribosomal gene rpl8 was also included in the same PCR reaction as an internal control, although the rpl8 result was shown only for the intestine in (B). The LGR5 expression shown in (C) was normalized against rpl8 expression determined at the same time.