Expression and processing of small integrin-binding ligand N-linked glycoproteins in mouse odontoblastic cells.
OBJECTIVE
Small integrin-binding ligand N-linked glycoproteins (SIBLINGs) are expressed in dentin and believed to control dentinogenesis. Five members of SIBLING family include bone sialoprotein (BSP), osteopontin (OPN), matrix extracellular phosphoglycoprotein (MEPE), dentin matrix protein 1 (DMP1) and dentin sialophosphoprotein (DSPP). These genes are clustered on chromosome 4q in humans and share similar biological features. DSPP and DMP1 are processed into given structural/functional fragments in rat and porcine. It still remains unclear whether these evidences occur in mouse and other SIBLING members are also processed into given fragments from their parent precursors. The aim of this study was to identify expression and processing of the five proteins in two mouse odontoblastic cell lines.


METHODS
Two mouse odontoblastic cells were used to study expression and processing of the five SIBLING proteins by immunohistochemistry and Western blot analyses.


RESULTS
Immunohistochemistry study showed that all of the five SIBLING members were expressed within the cytoplasm and cellular processes in the mouse odontoblastic cell lines. Expression levels of DMP1 and DSPP were higher in differentiated mouse odontoblasts than undifferentiated mouse odontoblasts. Immunolabelling signal of DSP and MEPE was also detected within the nucleus in the two cell lines. Western blot assay indicated that all five members were processed into at least two fragments in these cells.


CONCLUSIONS
These results suggest that different processed products and expression levels of the SIBLING proteins may play distinct biological functions in tooth development and mineralisation.
Chen
Shuo
S
Department of Pediatric Dentistry, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA. Chens0@uthscsa.edu
Chen
Lei
L
Jahangiri
Allen
A
Chen
Bo
B
Wu
Yimin
Y
Chuang
Hui-Hsiu
HH
Qin
Chunlin
C
MacDougall
Mary
M
D000818:Animals; D003810:Dentinogenesis / Q000235:genetics; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D015870:Gene Expression; D007150:Immunohistochemistry; D058574:Integrin-Binding Sialoprotein; D008024:Ligands; D051379:Mice; D008856:Microscopy, Fluorescence; D009804:Odontoblasts / Q000378:metabolism*; D053495:Osteopontin / Q000378:metabolism; D010750:Phosphoproteins; D011485:Protein Binding / Q000235:genetics; D011498:Protein Precursors / Q000378:metabolism; D012795:Sialoglycoproteins / Q000235:genetics / Q000378:metabolism*; D000099311:Dentin Sialophosphoprotein
D016326:Extracellular Matrix Proteins; D058574:Integrin-Binding Sialoprotein; D008024:Ligands; D053495:Osteopontin; D010750:Phosphoproteins; D011498:Protein Precursors; D012795:Sialoglycoproteins; D000099311:Dentin Sialophosphoprotein; C513308:Dmp1 protein, mouse; C546871:IBSP protein, human; C546872:Ibsp protein, mouse; C546873:Ibsp protein, rat