Expression of bone morphogenetic proteins and rat distal-less homolog genes following rat femoral fracture.
Expression of the genes encoding bone morphogenetic proteins (BMPs), BMP type IA receptor (BMPR-1A), and rat distal-less homolog (rDlx) was studied in bone, callus, and the surrounding soft tissue following rat femoral closed fracture, using RT-PCR-based techniques. Before fracture, the genes encoding BMP-5, BMP-6, and BMPR-1A were found to be expressed in both bone and the surrounding soft tissue, whereas the BMP-2 gene was expressed only in bone and BMP-7 was not expressed in either tissue. Expression of these genes was unaffected by fracture. The gene encoding BMP-4 was also expressed in both bone and the surrounding soft tissue before fracture. Moreover, although unchanged in bone, 6 h after fracture BMP-4 expression was increased tenfold in the surrounding soft tissue. The increased BMP-4 expression was transient and returned to prefracture levels within 72 h. Expression of rDlx was also increased in bone after fracture, but at later times than were observed with BMP-4: elevated rDlx expression was detected after 48 h and persisted for 30 days or more. No expression of rDlx was observed in the surrounding soft tissue before or after fracture. These findings indicate that BMP-4 and rDlx are selectively expressed following femoral fracture in the rat, and also suggest that they are involved in the formation of the callus at an early point during the postfracture healing of bone.
Yaoita
H
H
Department of Biochemistry and Molecular Biology, Nippon Medical School, Tokyo, Japan.
Orimo
H
H
Shirai
Y
Y
Shimada
T
T
D000469:Alkaline Phosphatase / Q000097:blood; D000818:Animals; D015139:Blotting, Southern; D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D055417:Bone Morphogenetic Protein 5; D052005:Bone Morphogenetic Protein Receptors, Type I; D019485:Bone Morphogenetic Proteins / Q000096:biosynthesis* / Q000235:genetics; D005264:Femoral Fractures / Q000235:genetics / Q000378:metabolism*; D017102:Fracture Healing / Q000235:genetics*; D005786:Gene Expression Regulation; D018398:Homeodomain Proteins / Q000096:biosynthesis* / Q000235:genetics; D007527:Isoenzymes / Q000097:blood; D008297:Male; D015675:Osteocalcin / Q000097:blood; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D017978:Receptors, Growth Factor / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000096:biosynthesis* / Q000235:genetics; D016212:Transforming Growth Factor beta
C525720:Bmp2 protein, rat; C525811:Bmp4 protein, rat; D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D055417:Bone Morphogenetic Protein 5; D019485:Bone Morphogenetic Proteins; C088334:Distal-less homeobox proteins; D018398:Homeodomain Proteins; D007527:Isoenzymes; D017978:Receptors, Growth Factor; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D015675:Osteocalcin; D017346:Protein Serine-Threonine Kinases; D052005:Bone Morphogenetic Protein Receptors, Type I; D000469:Alkaline Phosphatase