Human Cart-1: Structural Organization, Chromosomal Localization, and Functional Analysis of a Cartilage-Specific Homeodomain cDNA

ABSTRACT Homeoproteins control cell fates during development, specifying pattern formation and the ontogeny of specific tissues and organs in embryogenesis. Cart-1 cDNA was recently cloned from a rat chondrosarcoma tumor and it encodes a protein containing a paired-like homeodomain that is selectively expressed in cartilage during early chondrocyte differentiation. Here we report the molecular cloning of the human Cart-1 cDNA from a HeLa cervical carcinoma cDNA library. The human Cart-1 cDNA sequence is 88% identical and the deduced amino acid sequence is 95% identical to the rat sequence, indicating that Cart-1 structure is highly conserved. Northern and reverse transcriptase polymerase chain reaction (RT-PCR) analysis revealed Cart-1 mRNA expression in HeLa cervical carcinoma cells and human cervical tissue, but Cart-1 mRNA was not detected in GH3 rat pituitary cells and murine 10T½ one-half fibroblast cells. The Cart-1 gene was localized to human chromosome 12 and regionally mapped to the 12q21.3–q22 b...