Molecular cloning and characterization of NAG-7: a novel gene downregulated in human nasopharyngeal carcinoma.
OBJECTIVE
To identify novel tumor suppressor genes at chromosome 3p24-26 in human nasopharyngeal carcinoma (NPC).


METHODS
Twenty epithelial-derived expressed sequence tags (EST) were selected from chromosome 3p24-26. RT-PCR and Northern blot were used to detect the expression of the ESTs in NPC cell line, HNE-1, and primary cultures of normal nasopharyngeal epithelial cells. One EST, which was substantially downregulated in the HNE-1 cell line, was detected in 19 NPC biopsy samples. cDNA library screening was used to get its full sequence and the sequence of this novel gene was analyzed.


RESULTS
A novel gene located at chromosome 3p25.3 was obtained and named NAG-7. It was downregulated in 26.3% (5/19) of NPC biopsy samples. Its 1677 bp full length cDNA had a potential open reading frame predicting a 94 amino acid protein with a molecular weight of 11,023.87 Dalton. Analysis of the NAG-7 gene showed that it was a transmembrane protein containing a protein kinase C phosphorylation site and a myristyl site. It has no significant homology to any reported genes in the database of GenBank.


CONCLUSIONS
NAG-7 is a novel gene downregulated in NPC, suggesting that it may be involved in the development of NPC.
Xie
Y
Y
Laboratory of Cellular/Molecular Genetics, Cancer Research Institute, Hunan Medical University, Changsha 410078, China.
Bin
L
L
Yang
J
J
Li
Z
Z
Yu
Y
Y
Zhang
X
X
Cao
L
L
Li
G
G
D000595:Amino Acid Sequence; D001483:Base Sequence; D002893:Chromosomes, Human, Pair 3; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry; D015536:Down-Regulation; D020224:Expressed Sequence Tags; D015972:Gene Expression Regulation, Neoplastic; D016147:Genes, Tumor Suppressor; D006801:Humans; D008969:Molecular Sequence Data; D009303:Nasopharyngeal Neoplasms / Q000235:genetics*
D018076:DNA, Complementary