Human Cart-1: structural organization, chromosomal localization, and functional analysis of a cartilage-specific homeodomain cDNA.
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 10T1/2 one-half fibroblast cells. The Cart-1 gene was localized to human chromosome 12 and regionally mapped to the 12q21.3-q22 by PCR analysis of rodent-X-human somatic cell hybrid DNA and the CEPH megabase-insert YAC DNA pools, respectively. The Holt-Oram syndrome, characterized by upper limb and atrial septal dysplasias, also maps to the 12q21.3-q22 region. Cotransfection studies show that Cart-1 inhibits the rat prolactin promoter and that this repression is mediated by footprint II, an AT-rich element that functions as an inhibitory site of prolactin gene expression in nonpituitary cells and which was used to clone Cart-1. Taken together, these data indicate that Cart-1 may also influence cervix development, identify a putative DNA binding site for Cart-1, and, begin to define its functional role as modulator of gene expression.
Gordon
D F
DF
Department of Medicine, University of Colorado, Health Sciences Center, Denver 80262, USA.
Wagner
J
J
Atkinson
B L
BL
Chiono
M
M
Berry
R
R
Sikela
J
J
Gutierrez-Hartmann
A
A
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002277:Carcinoma; D002356:Cartilage / Q000378:metabolism*; D002584:Cervix Uteri / Q000378:metabolism*; D002874:Chromosome Mapping; D002881:Chromosomes, Human, Pair 12; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D015870:Gene Expression; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D006822:Hybrid Cells; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014407:Tumor Cells, Cultured; D002583:Uterine Cervical Neoplasms
C489985:ALX1 protein, human; C083282:Alx1 protein, rat; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D012333:RNA, Messenger