Genome‐wide DNA methylation and transcription analysis in tongue and biceps femoris muscles of cloned pigs with macroglossia

Abstract

Summary Cloned animals are prone to abnormal phenotypes such as enlarged tongue, fetal oversize, and progeria. In the present study, whole‐genome bisulfite sequencing and mRNA sequencing were performed on tongue and biceps femoris muscles of cloned piglets with and without macroglossia, in an attempt to elucidate the epigenetic causes of the macroglossia phenotype. We identified 14 958 and 18 752 differentially methylated regions in the tongue and biceps femoris muscles, respectively, of macroglossia piglets and these correspond to 4574 and 4772 differentially methylated genes compared with the control group (piglets without macroglossia). Larger methylation difference was found in tongue muscle than in biceps femoris muscle. In total, 114 genes in tongue and 72 genes in biceps femoris muscles were found to be differentially expressed between the two groups. Of these differentially expressed genes in tongue muscle, 31 were also differentially methylated genes, among which DIO3 and ZIC1 were imprinting or predicted imprinting genes. These two and another six overlapping genes (ALDH1A2, MKX, MAB21L2, CA3, RANBP3L, and MYL10) are crucial factors involved in embryonic development or tissue and organ development. GO enrichment analysis suggested possible alteration of these processes. Our study provides novel molecular insights into the formation of macroglossia in cloned pigs.

Characterization of Enlarged Tongues in Cloned Piglets

“…In the present study, we found some developmental defects including abnormal front legs, enlarged tongue, and hernia. We decided to analyze only enlarged tongue because that was the highest prevalence rate in a previous report by Yang et al [16]. As shown in Figure 4, we confirmed for the first time that the enlarged tongue from a cloned piglet exhibits very strange patterns of broken and isolated muscle bundles.…”

“…As described above in the introduction section, one of the reasons for decreasing the efficiency of cloning in pigs is developmental defects such as being overweight, giant forelimbs, atrophy of tendons, enlarged tongue, and exomphalos [13][14][15][16]. In the present study, we found some developmental defects including abnormal front legs, enlarged tongue, and hernia.…”

“…Also, some reports suggested that incomplete epigenetic reprogramming of the donor cell causes developmental defects resulting in low efficiency of SCNT [10][11][12]. Many kinds of symptoms from cloned pigs were reported including over-weight, giant forelimbs, atrophy of tendons, enlarged tongue, and exomphalos [13][14][15][16]. Among these, the incidence of abnormally enlarged tongues is higher compared to other symptoms, but the causes and mechanisms of its occurrence have not yet been fully understood [14,16,17].…”

Transcriptome analysis of mRNA and miRNA in the development of LeiZhou goat muscles

“…For example, Lyu et al 28 discovered that chi-miR-487b-3p regulates goat myoblast growth by targeting IRS1 and affecting the PI3K/Akt signaling pathway, thereby inhibiting skeletal myogenesis. Liu et al 29 established that miR-124a functions as a regulatory factor for VMP1 in muscle tissue. Modulating the expression of miR-124a, either through overexpression or inhibition, can exert effects on myoblast proliferation and autophagy.…”