title: Interference of kallikrein 1b26 (klk1b26) translation by microRNA specifically expressed in female mouse submandibular glands: an additional mechanism for sexual dimorphism of klk1b26 protein in the glands.
abstract: BACKGROUND
  Mouse kallikrein 1b26 (klk1b26) protein is more abundant in male submandibular glands (SMGs) than in female ones. This sexual dimorphism has been thought to be due to increased mRNA synthesis stimulated by androgen. However, the klk1b26 protein level in female SMG is far less than that expected from the mRNA level, suggesting an additional mechanism for down-regulation of klk1b26 expression in female SMGs.
  
  
  METHODS
  We examined the effects of small non-coding RNAs in mouse SMGs on in vitro translation of klk1b26 using a reticulocyte lysate system and reverse transcription (RT)-PCR for klk1b26 mRNA. Statistical analyses were performed with a computer package (Microsoft Excel).
  
  
  RESULTS
  The microRNA (miRNA) preparation from female SMGs, but not male SMGs, interfered with the in vitro translation of the klk1b26 protein and inhibited the RT-PCR for klk1b26 mRNA with forward primers targeting its 5'-terminal region (between the 15th and 40th nucleotide from the 5'-terminal). The miRNA preparation from castrated mouse SMGs showed the inhibitory effect on the klk1b26 translation, but that from a 5α-dihydrotestosterone-treated female mouse SMGs did not. Synthetic miRNAs (miR-325 and miR-1497a), which have partial complementarity with klk1b26 mRNA at its 5'-terminal region (15th to 40th nucleotide position from the 5'-terminal), also interfered with the in vitro klk1b26 translation. When the female miRNA preparation was incubated with a 30-nucleotide-long single-strand oligoDNA (named [15th-44th]ssDNA, whose sequence corresponded to the 15th to 44th position from the 5'-terminal of klk1b26 mRNA) prior to the addition into the in vitro translation system, the inhibitory effect of the miRNA preparation on klk1b26 translation disappeared, while [15th-44th]ssDNA itself had no effect on the translation. Preincubation of the miRNA preparation with another single-strand DNA ([169th-198th]ssDNA, whose sequence corresponded with 169th to 198th position of klk1b26 mRNA) did not show the inhibitory effect.
  
  
  CONCLUSIONS
  The small non-coding RNA, most probably miRNA, specifically expressed in female mouse SMGs interfered with klk1b26 protein synthesis in the in vitro translation system. Therefore sexual dimorphism observed in klk1b26 expression in mouse SMGs is due at least in part to the female-specific small non-coding RNA in SMGs.
authors.affiliation: Department of Physiology, Meikai University School of Dentistry, Sakado, Saitama 350-0283, Japan. kkinji@dent.meikai.ac.jp.
authors.forename: Kinji
authors.initials: K
authors.lastname: Kurihara
authors.forename: Nobuo
authors.initials: N
authors.lastname: Nakanishi
authors.forename: Akito
authors.initials: A
authors.lastname: Tomomura
references.citation: Trends Cell Biol. 2007 Mar;17(3):118-26
references.pmid: 17197185
references.citation: Cell. 2001 Dec 28;107(7):823-6
references.pmid: 11779458
references.citation: Nucleic Acids Res. 2007;35(17):5944-53
references.pmid: 17726050
references.citation: Proc Natl Acad Sci U S A. 2004 Jan 6;101(1):360-5
references.pmid: 14691248
references.citation: Cell. 2007 Jun 29;129(7):1401-14
references.pmid: 17604727
references.citation: Am J Physiol Cell Physiol. 2000 Nov;279(5):C1516-27
references.pmid: 11029299
references.citation: Genome Biol. 2010;11(5):R56
references.pmid: 20507594
references.citation: Biochim Biophys Acta. 1968 Feb 1;156(1):51-8
references.pmid: 5645751
references.citation: Nature. 2008 Dec 18;456(7224):980-4
references.pmid: 19043405
references.citation: Nature. 2000 Mar 16;404(6775):293-6
references.pmid: 10749213
references.citation: EMBO J. 2002 Sep 2;21(17):4663-70
references.pmid: 12198168
references.citation: Genome Res. 2009 Jan;19(1):92-105
references.pmid: 18955434
references.citation: Mol Biol Evol. 2008 Jun;25(6):1067-80
references.pmid: 18339653
references.citation: Biochem Pharmacol. 2003 Jul 15;66(2):239-50
references.pmid: 12826266
references.citation: Am J Physiol Cell Physiol. 2002 Apr;282(4):C817-23
references.pmid: 11880270
references.citation: Mol Cancer. 2010 May 17;9:108
references.pmid: 20478051
references.citation: Breast Cancer Res. 2010;12(2):201
references.pmid: 20346098
references.citation: J Biochem. 1994 Jan;115(1):137-43
references.pmid: 8188620
references.citation: Am J Physiol. 1999 Dec;277(6):C1184-93
references.pmid: 10600770
references.citation: Nature. 2005 Jun 9;435(7043):828-33
references.pmid: 15944707
references.citation: Science. 2001 Aug 10;293(5532):1146-50
references.pmid: 11498593
references.citation: Nature. 2008 Oct 23;455(7216):1124-8
references.pmid: 18806776
references.citation: Nat Rev Genet. 2008 Dec;9(12):911-22
references.pmid: 19002143
references.citation: Arch Oral Biol. 1985;30(10):727-30
references.pmid: 3910007
references.citation: Curr Genomics. 2009 May;10(3):154-68
references.pmid: 19881909
references.citation: Arch Oral Biol. 2008 Jul;53(7):593-604
references.pmid: 18304517
references.citation: Mol Hum Reprod. 2010 Jul;16(7):463-71
references.pmid: 20215419
references.citation: Horm Metab Res. 1999 Jun;31(6):370-4
references.pmid: 10437626
references.citation: Cell. 2003 Oct 17;115(2):209-16
references.pmid: 14567918
references.citation: Eur J Morphol. 1996 Aug;34(3):221-4
references.pmid: 8874100
references.citation: J Biol Chem. 1962 May;237:1555-62
references.pmid: 13880319
references.citation: Endocrinology. 1992 Feb;130(2):1044-55
references.pmid: 1733706
references.citation: Science. 2003 Mar 7;299(5612):1540
references.pmid: 12624257
references.citation: Physiol Rev. 1968 Jul;48(3):534-69
references.pmid: 4875350
references.citation: Endocrinology. 1999 Jul;140(7):3003-11
references.pmid: 10385392
references.citation: Acta Chem Scand. 1966;20(3):820-34
references.pmid: 5958830
references.citation: Genes Dev. 2010 May 15;24(10):992-1009
references.pmid: 20413612
references.citation: J Histochem Cytochem. 2004 Nov;52(11):1437-46
references.pmid: 15505338
references.citation: Cell. 2003 Oct 17;115(2):199-208
references.pmid: 14567917
references.citation: PLoS One. 2009 Oct 02;4(10):e7314
references.pmid: 19798417
references.citation: Mol Cell Endocrinol. 1988 Apr;56(3):271-6
references.pmid: 3286326
references.citation: J Biol Chem. 2010 Aug 6;285(32):25074-84
references.pmid: 20538601