Isolation and characterization of a novel cDNA, UBAP1, derived from the tumor suppressor locus in human chromosome 9p21-22.
OBJECTIVE
To clone the putative tumor suppressor gene(s) in a refined region at 9p21-22 undergoing loss of heterozygosity in nasopharyngeal carcinoma (NPC).


METHODS
We systematically screened the expression patterns of 25 novel ESTs (expressed sequence tags) in a minimal common deleted region of 9p21-22 in NPC. One of these ESTs was found down-regulated in NPC. Subsequently, the corresponding gene sequence of this EST was established by cDNA cloning and RACE (rapid amplification of cDNA end) procedures. Furthermore, a mouse homologue of this gene was identified. The expression of this gene was examined using Northern blot or reverse transcription-polymerase chain reaction (RT-PCR) in various human and mouse tissues. A limited screen for mutation of coding sequence of this novel human gene was undertaken using RT-PCR and direct sequencing analysis.


RESULTS
A novel gene was cloned. This gene is a new member of the UBA domain family, so we named it UBAPI for ubiquitin-associated protein 1 (HUGO Gene Nomenclature Committee-approved symbol). Northern blot and RT-PCR analysis demonstrate a ubiquitous pattern of gene expression in human and mouse tissues. The direct sequencing analysis of the coding region of hUBAP1 following RT-PCR failed to reveal any mutations in a preliminary screen of NPC cell line HNE1 and primary nasopharyngeal carcinoma samples.


CONCLUSIONS
We cloned a novel gene UBAPI, which is highly conserved between human and mouse. Clearly, as a novel member of UBA domain protein family and taking its map location into account, a more extensive analysis is essential to establish whether subtle mutations are present in nasopharyngeal carcinomas.
Qian
J
J
Cancer Research Institute, Human Medical University, Changsha, PR China.
Yang
J
J
Zhang
X
X
Zhang
B
B
Wang
J
J
Zhou
M
M
Tang
K
K
Li
W
W
Zeng
Z
Z
Zhao
X
X
Shen
S
S
Li
G
G
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D002899:Chromosomes, Human, Pair 9; D018076:DNA, Complementary; D020224:Expressed Sequence Tags; D005786:Gene Expression Regulation; D016147:Genes, Tumor Suppressor; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009303:Nasopharyngeal Neoplasms / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D018076:DNA, Complementary