TY - JOUR
T1 - Analysis of type-I and type-II RUNX2 protein expression in osteoblasts
AU - Sudhakar, Sivasubramaniam
AU - Katz, Michael S.
AU - Elango, Narayanasamy
N1 - Funding Information:
This work was supported by grants from the American Federation for Aging Research and Veterans Integrated Service Network (VISN) 17 (to N. Elango), and from the Department of Veterans Affairs (to M. S. Katz).
PY - 2001
Y1 - 2001
N2 - Runt-related transcription factor-2 (RUNX2) is expressed as two isoforms (type-I and type-II) differing only in their amino terminal sequences. The amino terminus of type-I contains MRIPV instead of MASNSLF-SAVTPCQQSFFW in type-II. Although type-II mRNA has been considered osteoblast specific, the RUNX2 protein isoforms expressed in osteoblasts have not yet been identified. Using antisera generated against the two different amino terminal sequences of type-I and type-II RUNX2, we show the expression of both isoforms in cells with the mature osteoblast phenotype (fetal rat calvarial cells, and ROS 17/2.8, SaOS-2 and U2OS osteosarcoma cell lines), but only type-I in partially differentiated osteoblast-like cells (the UMR-106 osteosarcoma cell line). Since UMR-106 cells express both type. I and type. II mRNAs, our results suggest that the translation of type-II mRNA is repressed in these cells. No RUNX1 and RUNX3 proteins are detected in any of the osteoblastic cells tested. The antisera we have generated will be useful for studies relating expression of RUNX2 isoforms to control of osteoblast differentiation.
AB - Runt-related transcription factor-2 (RUNX2) is expressed as two isoforms (type-I and type-II) differing only in their amino terminal sequences. The amino terminus of type-I contains MRIPV instead of MASNSLF-SAVTPCQQSFFW in type-II. Although type-II mRNA has been considered osteoblast specific, the RUNX2 protein isoforms expressed in osteoblasts have not yet been identified. Using antisera generated against the two different amino terminal sequences of type-I and type-II RUNX2, we show the expression of both isoforms in cells with the mature osteoblast phenotype (fetal rat calvarial cells, and ROS 17/2.8, SaOS-2 and U2OS osteosarcoma cell lines), but only type-I in partially differentiated osteoblast-like cells (the UMR-106 osteosarcoma cell line). Since UMR-106 cells express both type. I and type. II mRNAs, our results suggest that the translation of type-II mRNA is repressed in these cells. No RUNX1 and RUNX3 proteins are detected in any of the osteoblastic cells tested. The antisera we have generated will be useful for studies relating expression of RUNX2 isoforms to control of osteoblast differentiation.
KW - Osteoblast differentiation
KW - RUNX2 specific antibodies
KW - Transcription factor
KW - Translational regulation
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U2 - 10.1006/bbrc.2001.5363
DO - 10.1006/bbrc.2001.5363
M3 - Article
C2 - 11485310
AN - SCOPUS:0034810744
VL - 286
SP - 74
EP - 79
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
IS - 1
ER -