Cartilage homeoprotein 1, a homeoprotein selectively expressed in chondrocytes.
We identified a rat cDNA that encodes cartilage homeoprotein 1 (Cart-1). The deduced amino acid sequence of Cart-1 contains a paired-type homeodomain. Northern blot hybridization and RNase protection assay revealed that Cart-1 RNA was present at high levels in a well-differentiated rat chondrosarcoma tumor and in a cell line derived from this tumor. Cart-1 RNA was detected in primary mouse and rat chondrocytes but not in various fibroblasts including mouse 10T1/2 cells, NIH 3T3 cells, BALB 3T3 cells, and rat skin fibroblasts. It was also undetectable in mouse C2 myoblasts, S194 myeloma cells, and embryonic stem cells. Cart-1 RNA was present at a very low level in tested but was not detected in other soft tissues of 8-week-old rats. In situ hybridization of rat embryos between 14.5 and 16.5 days post coitum revealed relatively high levels of Cart-1 RNA in condensed prechondrocytic mesenchymal cells and in early chondrocytes of cartilage primordia. The levels of Cart-1 RNA were lower in mature chondrocytes. No hybridization was observed in brain, spinal cord, heart, spleen, gastrointestinal tract, liver, and muscle. We speculate that Cart-1 has a role in chondrocyte differentiation.
Zhao
G Q
GQ
Department of Molecular Genetics, University of Texas M. D. Anderson Cancer Center, Houston 77030.
Zhou
X
X
Eberspaecher
H
H
Solursh
M
M
de Crombrugghe
B
B
D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002356:Cartilage / Q000378:metabolism*; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D004622:Embryo, Mammalian; D018398:Homeodomain Proteins; D017403:In Situ Hybridization; D051379:Mice; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D009928:Organ Specificity; D011061:Poly A / Q000235:genetics / Q000302:isolation & purification; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D012333:RNA, Messenger; D051381:Rats; D015183:Restriction Mapping; D012867:Skin / Q000378:metabolism
C489986:Alx1 protein, mouse; C083282:Alx1 protein, rat; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger; D011061:Poly A; D012313:RNA; D004247:DNA