title: Identification and characterization of microRNA sequences from bovine mammary epithelial cells.
abstract: The bovine mammary gland is composed of various cell types including bovine mammary epithelial cells (BMEC). The use of BMEC to uncover the microRNA (miRNA) profile would allow us to obtain a more specific profile of miRNA sequences that could be associated with lactation and avoid interference from other cell types. The objective of this study was to characterize the miRNA sequences expressed in isolated BMEC. The miRNA were identified by Solexa sequencing technology (Illumina Inc., San Diego, CA). Furthermore, novel miRNA were uncovered by stem-loop reverse transcription-PCR and sequencing of PCR products. To detect tissue specificity, expression of novel miRNA sequences was measured by stem-loop RT-PCR and sequencing of PCR products in mammary gland, liver, adipose, ileum, spleen and kidney tissue from 3 lactating Holstein cows (50±10 d postpartum). After bioinformatics analysis, 12,323,451 reads were obtained by Solexa sequencing, of which 11,979,706 were clean reads, matching the bovine genome. Among clean reads, 9,428,122 belonged to miRNA sequences. Further analysis revealed that the miRNA bta-mir-184 had the most abundant expression, and 388 loci possessed the typical stem-loop structures matching known miRNA hairpins. In total, 38 loci with novel hairpins were identified as novel miRNA and were numbered from bta-U1 to bta-U38. One novel miRNA (bta-U21) was specific to mammary gland. Seven novel miRNA, including bta-U21, had tissue-restricted distribution. Uncovering the specific roles of these novel miRNA during lactation appears warranted.
authors.affiliation: State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Science, Beijing, 100193, China; Chinese Academy of Agricultural Sciences (CAAS)-International Centre for Research in Agroforestry (ICRAF), World Agroforestry Centre, East and Central Asia, Beijing 100081, China; Synergetic Innovation Center of Food Safety and Nutrition, Harbin, 150030, China.
authors.forename: D P
authors.initials: DP
authors.lastname: Bu
authors.affiliation: State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Science, Beijing, 100193, China; Synergetic Innovation Center of Food Safety and Nutrition, Harbin, 150030, China.
authors.forename: X M
authors.initials: XM
authors.lastname: Nan
authors.affiliation: State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Science, Beijing, 100193, China; Chinese Academy of Agricultural Sciences (CAAS)-International Centre for Research in Agroforestry (ICRAF), World Agroforestry Centre, East and Central Asia, Beijing 100081, China.
authors.forename: F
authors.initials: F
authors.lastname: Wang
authors.affiliation: Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana 61801. Electronic address: jloor@illinois.edu.
authors.forename: J J
authors.initials: JJ
authors.lastname: Loor
authors.affiliation: State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Science, Beijing, 100193, China. Electronic address: jqwangcaas@gmail.com.
authors.forename: J Q
authors.initials: JQ
authors.lastname: Wang
mesh_terms: D000818:Animals; D002417:Cattle / Q000235:genetics* / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D020869:Gene Expression Profiling / Q000662:veterinary; D059014:High-Throughput Nucleotide Sequencing / Q000662:veterinary; D008321:Mammary Glands, Animal / Q000378:metabolism; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism
chemical_list: D035683:MicroRNAs
keywords: bovine mammary epithelial cell; novel microRNA; sequencing