title: Expression of Runx2 transcription factor in non-skeletal tissues, sperm and brain.
abstract: Runx2 is a master transcription factor for chondrocyte and osteoblast differentiation and bone formation. However expression of Runx2 (by RT-PCR), has been reported in non-skeletal tissues such as breast, T cells and testis. To better define Runx2 activity in non-skeletal tissues, we examined transgenic (Tg) mice expressing LacZ gene under control of 3.0 kb (3 kb Tg) or 1.0 kb (1 kb Tg) of the Runx2 distal (P1) promoter, Runx2 LacZ knock-in (Runx2(+/LacZ)) and Runx2/P1 LacZ knock-in (Runx2/P1(+/LacZ)). In the Runx2 3 kb Tg mouse, beta-galactosidase (beta-gal) expression appeared in various non-skeletal tissues including testis, skin, adrenal gland and brain. beta-gal expression from both 3 kb and 1 kb Tg, reflecting activity of the Runx2 promoter, was readily detectable in seminiferous tubules of the testis and the epididymis. At the single cell level, beta-gal was detected in spermatids and mature sperms not in sertoli or Leydig cells. We also detected a positive signal from the Runx2(+/LacZ) and Runx2/P1(+/LacZ) mice. Indeed, Runx2 expression was observed in isolated mature sperms, which was confirmed by RT-PCR and Western blot analysis. Runx2, however, was not related to sex determination and sperm motility. Runx2 mediated beta-gal activity is also found robustly in the hippocampus and frontal lobe of the brain in Runx2(+/LacZ). Collectively, these results indicate that Runx2 is expressed in several non-skeletal tissues particularly sperms of testis and hippocampus of brain. It suggests that Runx2 may play an important role in male reproductive organ testis and brain.
authors.affiliation: Department of Biochemistry and Cell Biology, School of Medicine, Cell and Matrix Research Institute, Skeletal Diseases Genome Research Center, Kyungpook National University, Daegu, Republic of Korea.
authors.forename: Jae-Hwan
authors.initials: JH
authors.lastname: Jeong
authors.forename: Jung-Sook
authors.initials: JS
authors.lastname: Jin
authors.forename: Hyun-Nam
authors.initials: HN
authors.lastname: Kim
authors.forename: Sang-Min
authors.initials: SM
authors.lastname: Kang
authors.forename: Julie C
authors.initials: JC
authors.lastname: Liu
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Lengner
authors.forename: Florian
authors.initials: F
authors.lastname: Otto
authors.forename: Stefan
authors.initials: S
authors.lastname: Mundlos
authors.forename: Janet L
authors.initials: JL
authors.lastname: Stein
authors.forename: Andre J
authors.initials: AJ
authors.lastname: van Wijnen
authors.forename: Jane B
authors.initials: JB
authors.lastname: Lian
authors.forename: Gary S
authors.initials: GS
authors.lastname: Stein
authors.forename: Je-Yong
authors.initials: JY
authors.lastname: Choi
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism*; D002460:Cell Line; D050659:Core Binding Factor Alpha 1 Subunit / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005625:Frontal Lobe / Q000378:metabolism; D017930:Genes, Reporter; D006624:Hippocampus / Q000378:metabolism; D007763:Lac Operon; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D010053:Ovary / Q000378:metabolism; D011401:Promoter Regions, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019849:Sex Determination Processes; D013081:Sperm Motility; D013091:Spermatogenesis; D013094:Spermatozoa / Q000378:metabolism*
chemical_list: D050659:Core Binding Factor Alpha 1 Subunit; C493716:Runx2 protein, mouse