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Identification of baboon microRNAs expressed in liver and lymphocytes

MicroRNAs (miRNAs) are small noncoding RNAs (~22 nucleotides) that regulate gene expression by cleaving mRNAs or inhibiting translation. The baboon is a well-characterized cardiovascular disease model; however, no baboon miRNAs have been identified. Evidence indicates that the baboon and human genomes are highly conserved; based on this conservation, we hypothesized that comparative genomic methods could be used to identify baboon miRNAs. Methods: We employed an in silico comparative genomics approach and human miRNA arrays to identify baboon expressed miRNAs in liver (n = 6) and lymphocytes (n = 6). Expression profiles for selected miRNAs in multiple tissues were validated by. | Karere et al. Journal of Biomedical Science 2010 17 54 http www.jbiomedsci.eom content 17 1 54 a NSC Tha cost of publication In Journal of Blomodlcal Science Is boms by tlM National Science Council Taiwan JOURNAL OF BIOMEDICAL SCIENCE RESEARCH Open Access Identification of baboon microRNAs expressed in liver and lymphocytes Genesio M Karere 1 Jeremy P Glenn1 John L VandeBerg1 2 and Laura A Cox 1 2 Abstract Background MicroRNAs miRNAs are small noncoding RNAs 22 nucleotides that regulate gene expression by cleaving mRNAs or inhibiting translation. The baboon is a well-characterized cardiovascular disease model however no baboon miRNAs have been identified. Evidence indicates that the baboon and human genomes are highly conserved based on this conservation we hypothesized that comparative genomic methods could be used to identify baboon miRNAs. Methods We employed an in silico comparative genomics approach and human miRNA arrays to identify baboon expressed miRNAs in liver n 6 and lymphocytes n 6 . Expression profiles for selected miRNAs in multiple tissues were validated by RT-PCR. Results We identified in silico 555 putative baboon pre-miRNAs of which 41 exhibited 100 identity and an additional 58 shared more than 90 sequence identity with human pre-miRNAs. Some of these miRNAs are primatespecific and are clustered in the baboon genome like human miRNA clusters. We detected expression of 494 miRNAs on the microarray and validated expression of selected miRNAs in baboon liver and lymphocytes by RT-PCR. We also observed miRNA expression in additional tissues relevant to dyslipidemia and atherosclerosis. Approximately half of the miRNAs expressed on the array were not predicted in silico suggesting that we have identified novel baboon miRNAs which could not be predicted using the current draft of the baboon genome. Conclusion We identified a subset of baboon miRNAs using a comparative genomic approach identified additional baboon miRNAs using a human array and showed