title: Multiple promoters and targeted microRNAs direct the expressions of HMGB3 gene transcripts in dairy cattle.
abstract: HMGB3 (high-mobility group box 3) is an X-linked member of a family of sequence-independent chromatin-binding proteins and functions as a universal sentinel for nucleic acid-mediated innate immune responses. The splice variant expression, promoter characterization and targeted microRNAs of the bovine HMGB3 gene were investigated to explore its expression pattern and possible regulatory mechanism. The results revealed that the expression of HMGB3 transcript variants 1 and 2 (HMGB3-TV1 and HMGB3-TV2) mRNA in the mastitis-infected mammary gland tissues was up-regulated by 8.46- and 5.31-fold respectively compared with that in healthy tissues (P < 0.05). HMGB3-TV1 was highly expressed in the mammary gland tissues, whereas HMGB3-TV2 was expressed primarily in liver. Functional analyses indicated that HMGB3 transcription is regulated by three distinct promoters - promoters 1, 2 and 3 (P1, P2 and P3) - resulting in two alternative transcripts with the same 3'-untranslated region. Promoter luciferase activity analysis suggested that the core sequences of P1 and P2 were mapped in the region of g.1535 to ~g.2076 and g.2074 to ~g.2491 respectively. The g.5880C>T SNP in P3 affected its base promoter activity, and different genotypes were associated with the bovine somatic count score. The expression of targets bovine miR-17-5p, miR-20b and miR-93 of the HMGB3 gene was down-regulated 1.56-, 1.72- and 2.94-fold respectively in mammary gland tissues as compared with that in healthy tissues (P < 0.05). The findings suggest that HMGB3 expression is under complex transcriptional and post-transcriptional control by alternate promoter usage, alternative splicing mechanism and microRNAs in dairy cattle.
authors.affiliation: Laboratory of Molecular Genetics and Breeding, Dairy Cattle Research Center, Shandong Academy of Agricultural Sciences, Industry North Road 159, Jinan, Shandong, 250131, China.
authors.forename: Liming
authors.initials: L
authors.lastname: Li
authors.forename: Jinming
authors.initials: J
authors.lastname: Huang
authors.forename: Zhihua
authors.initials: Z
authors.lastname: Ju
authors.forename: Qiuling
authors.initials: Q
authors.lastname: Li
authors.forename: Changfa
authors.initials: C
authors.lastname: Wang
authors.forename: Chao
authors.initials: C
authors.lastname: Qi
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Qinlei
authors.initials: Q
authors.lastname: Hou
authors.forename: Suqin
authors.initials: S
authors.lastname: Hang
authors.forename: Jifeng
authors.initials: J
authors.lastname: Zhong
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D002417:Cattle; D019295:Computational Biology; D018899:CpG Islands; D005260:Female; D005838:Genotype; D057809:HEK293 Cells; D025765:HMGB3 Protein / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008414:Mastitis, Bovine / Q000235:genetics; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016385:TATA Box; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D015854:Up-Regulation
chemical_list: D025765:HMGB3 Protein; D035683:MicroRNAs; D012333:RNA, Messenger; D008156:Luciferases