Endogenous Msx1 antisense transcript: in vivo and in vitro evidences, structure, and potential involvement in skeleton development in mammals.
Msx1 is a key factor for the development of tooth and craniofacial skeleton and has been proposed to play a pivotal role in terminal cell differentiation. In this paper, we demonstrated the presence of an endogenous Msx1 antisense RNA (Msx1-AS RNA) in mice, rats, and humans. In situ analysis revealed that this RNA is expressed only in differentiated dental and bone cells with an inverse correlation with Msx1 protein. These in vivo data and overexpression of Msx1 sense and AS RNA in an odontoblastic cell line (MO6-G3) showed that the balance between the levels of the two Msx1 RNAs is related to the expression of Msx1 protein. To analyze the impact of this balance in the Msx-Dlx homeoprotein pathway, we analyzed the effect of Msx1, Msx2, and Dlx5 overexpression on proteins involved in skeletal differentiation. We showed that the Msx1-AS RNA is involved in crosstalk between the Msx-Dlx pathways because its expression was abolished by Dlx5. Msx1 was shown to down-regulate a master gene of skeletal cells differentiation, Cbfa1. All these data strongly suggest that the ratio between Msx1 sense and antisense RNAs is a very important factor in the control of skeletal terminal differentiation. Finally, the initiation site for Msx1-AS RNA transcription was located by primer extension in both mouse and human in an identical region, including a consensus TATA box, suggesting an evolutionary conservation of the AS RNA-mediated regulation of Msx1 gene expression.
Blin-Wakkach
C
C
Laboratory of Biology-Odontology, Institut National de la Santé et de la Recherche Médicale, E 0110, Institut des Cordeliers, IFR 58, 75006 Paris, France. biol_odonto_fr@yahoo.com
Lezot
F
F
Ghoul-Mazgar
S
S
Hotton
D
D
Monteiro
S
S
Teillaud
C
C
Pibouin
L
L
Orestes-Cardoso
S
S
Papagerakis
P
P
Macdougall
M
M
Robert
B
B
Berdal
A
A
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002460:Cell Line; D002645:Chickens; D017124:Conserved Sequence; D005314:Embryonic and Fetal Development; D019143:Evolution, Molecular; D018507:Gene Expression Regulation, Developmental; D006579:Heterozygote; D018398:Homeodomain Proteins / Q000235:genetics* / Q000502:physiology*; D006801:Humans; D051957:MSX1 Transcription Factor; D008322:Mammals; D051379:Mice; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D009804:Odontoblasts / Q000166:cytology / Q000502:physiology; D010012:Osteogenesis; D014176:Protein Biosynthesis; D016372:RNA, Antisense / Q000235:genetics*; D051381:Rats; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors; D014158:Transcription, Genetic
D018398:Homeodomain Proteins; D051957:MSX1 Transcription Factor; C497998:Msx1 protein, rat; D016372:RNA, Antisense; D014157:Transcription Factors