Turtle ghrelin

Pascual-Anaya et al. reply:

Although we reported that the GHRL gene encoding ghrelin was lost in turtle species (Pelodiscus sinensis and Chelonia mydas) on the basis of bioinformatics analysis of the genomes of these turtles¹, we have now confirmed that GHRL genes actually exist in these species. This finding reported by two independent studies that performed detailed reanalysis of the two turtle genomic sequences^2,3 was confirmed by our own PCR-based detection method in which we cloned and sequenced the cDNA encoding preproghrelin in P. sinensis adult tissues (Fig. 1 and Supplementary Note). The related Ensembl database has been updated to reflect this corrigendum (release 75, February 2014; new transcript ID ENSPSIT00000022826; Supplementary Figs. 1 and 2). As expected, ghrelin expression was high in stomach, albeit evaluated using non-normalized RT-PCR (Fig. 1). The protein sequences predicted on the basis of the P. sinensis genome by Seim and colleagues are identical to the protein sequences we predicted from our cloned, sequenced cDNA (Supplementary Note).

Figure 1: RT-PCR detection of mRNA encoding preproghrelin in P. sinensis adult tissues.

M, molecular weight marker; K, kidney; I, intestine; S, stomach; Sp, spleen; G, gall bladder; Mu, skeletal muscle; H, heart; B, brain; Li, liver; Lu, lung. See the Supplementary Note for a detailed description of the method used.