Expression of runtB is modulated during chondrocyte differentiation.
The runt locus in Drosophila encodes a nuclear protein involved in embryo segmentation, sex determination/X dosage compensation, and neurogenesis. runt homologues have been identified in higher vertebrates. The encoded proteins share a domain of 128 amino acids called the runt domain. It has been reported that this domain mediates DNA binding and heterodimerization. Here, we analyze runtB expression during chondrocyte differentiation "in vitro" and "in vivo." We have first isolated, from a chondrocyte library, a cDNA clone coding for a runtB chicken homologue and containing a complete open reading frame. The predicted protein product is 84% identical to the mouse PEBP2alphaB2 isoform. By RT-PCR analysis we have also cloned the chicken cDNA fragment coding for delta alphaB2, the exon sequence included in the B1 isoform mRNA. On Northern blot analysis of cultured chondrocytes, runtB mRNA levels increase dramatically with the transition from stage 0 (dedifferentiated) to stages I and II (hypertrophic chondrocytes). Moreover, runt polypeptides were demonstrated in chondrocytes both in vivo and in vitro. These results suggest that runt plays a role in chondrogenic differentiation.
Castagnola
P
P
Laboratorio di Differenziamento Cellulare, Istituto Nazionale per La Ricerca sul Cancro, Genoa, Italy.
Gennari
M
M
Gaggero
A
A
Rossi
F
F
Daga
A
A
Corsetti
M T
MT
Calabi
F
F
Cancedda
R
R
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002356:Cartilage / Q000166:cytology* / Q000378:metabolism; D002454:Cell Differentiation; D002478:Cells, Cultured; D002642:Chick Embryo; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics*; D029721:Drosophila Proteins; D005091:Exons / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D012333:RNA, Messenger / Q000032:analysis; D011993:Recombinant Fusion Proteins; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013977:Tibia; D014157:Transcription Factors
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; C080833:run protein, Drosophila