Background MicroRNAs (miRNAs) regulate adipose tissue development, which are closely related to subcutaneous and intramuscular fat deposition and adipocyte differentiation. As an important economic and agricultural animal, rabbits have low adipose tissue deposition and are an ideal model to study adipose regulation. However, the miRNAs related to fat deposition during the growth and development of rabbits are poorly defined. Methods In this study, miRNA-sequencing and bioinformatics analyses were used to profile the miRNAs in rabbit perirenal adipose tissue at 35, 85 and 120 days post-birth. Differentially expressed (DE) miRNAs between different stages were identified by DEseq in R. Target genes of DE miRNAs were predicted by TargetScan and miRanda. To explore the functions of identified miRNAs, Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed. Results Approximately 1.6 GB of data was obtained by miRNA-seq. A total of 987 miRNAs (780 known and 207 newly predicted) and 174 DE miRNAs were identified. The miRNAs ranged from 18 nt to 26 nt. GO enrichment and KEGG pathway analyses revealed that the target genes of the DE miRNAs were mainly involved in zinc ion binding, regulation of cell growth, MAPK signaling pathway, and other adipose hypertrophy-related pathways. Six DE miRNAs were randomly selected, and their expression profiles were validated by q-PCR. Conclusions This is the first report of the miRNA profiles of adipose tissue during different growth stages of rabbits. Our data provide a theoretical reference for subsequent studies on rabbit genetics, breeding and the regulatory mechanisms of adipose development.

45MiRNAs regulate adipose tissue development, which are closely 46 related to subcutaneous and intramuscular fat deposition and adipocyte 47 differentiation. As an important economic and agricultural animal, rabbits 48 have low adipose tissue deposition and are an ideal model to study 49 adipose regulation. However, the miRNAs related to fat deposition during 50 the growth and development of rabbits are poorly defined. In this study, 51 miRNA-sequencing and bioinformatics analyses were used to profile the 52 miRNAs in rabbit perirenal adipose tissue at 35, 85 and 120 days 53 post-birth. Differentially expressed (DE) miRNAs between different 54 stages were identified by DEseq in R. Target genes of DE miRNAs were 55 predicted by TargetScan and miRanda. To explore the functions of 56 identified miRNAs, Gene Ontology (GO) enrichment and Kyoto 57 Encyclopedia of Genes and Genomes (KEGG) pathway analyses were 58 performed. Approximately 1.6 GB of data was obtained by miRNA-seq. 59 A total of 987 miRNAs (780 known and 207 newly predicted) and 174 60 DE miRNAs were identified. The miRNAs ranged from 18nt to 26nt. GO 61 enrichment and KEGG pathway analyses revealed that the target genes of 62 the DE miRNAs were mainly involved in zinc ion binding, regulation of 63 cell growth, MAPK signaling pathway, and other adipose 64 hypertrophy-related pathways. Six DE miRNAs were randomly selected 65 and their expression profiles were validated by q-PCR. In summary, we 66 4 provide the first report of the miRNA profiles of rabbit adipose tissue 67 during different growth stages. Our data provide a theoretical reference 68 for subsequent studies on rabbit genetics, breeding and the regulatory 69 mechanisms of adipose development.70 Introduction 71 MicroRNAs (miRNAs) are endogenous non-coding RNAs, typically 72 18～26 nucleotides in length, that regulate gene expression in eukaryotic 73 cells. Mature miRNAs are produced from long primary transcripts 74 through a series of nucleases that are further assembled into 75 RNA-induced silencing complexes. These complexes recognize target 76 mRNAs by complementary base pairing, leading to mRNA degradation 77 and the inhibition of translation(Fabian et al. 2010). MiRNAs regulate a 78 wide range of physiological processes, including growth and 79 development, virus defense, cell proliferation, apoptosis and fat 80 metabolism. Meanwhile, it has been well documented that MiRNAs 81 regulate adipose tissue development, which are closely related to 82 subcutaneous and intramuscular fat deposition(Guoxi et al. 2011; Guo et 83 al. 2012) and adipocyte differentiation(Son et al. 2014).MiRNAs, 84 including miR-27b(Karbiener et al. 2009), miR-103(Meihang et al. 2015) 85 and miR-148a(Shi et al. 2015) regulate adipogenic processes, promoting 86 or inhibiting adipogenesis in animals. This implicates miRNAs can be a 87 5 new target for studying the molecular mechanisms governing fat 88 development, growth and deposition in animals. 89 To-date, studies on the role of miRNAs during fat development have 90 ...