Cloning and Expression
Analysis of a Novel Gene, UBAP1, Possibly
Involved in Ubiquitin Pathway
QIAN Jun, ZHANG Xiao-Hui, YANG Jian-Bo, WANG Jie-Ru，ZHANG Bi-Cheng, TANG Ke, LI
Gui-Yuan*
( Cancer Research Institute, Hunan Medical University, Changsha 410078,
China )
Abstract
The
9p21-22 region shows loss of heterozygosity in up to 60% of human
nasopharyngeal carcinomas (NPC), indicating the presence of a tumor suppressor
gene in this region. We have identified a novel minimal common deletion region
at 9p21-22. Twenty-two epithelial-derived expressed sequence tags(ESTs) in this
critical region were systematically screened by differential RT-PCR to
investigate the expression patterns in NPC cell line HNE1 and primary cultures
of normal nasopharyngeal epithelial cells. One of these ESTs was found
down-expressed in HNE1, whose differential expression was confirmed by Northern
blot. Subsequently the corresponding gene sequence for this EST was established
by cDNA cloning and RACE procedures (GenBank Accession No.AF222043).
Furthermore, a mouse homologueof this gene was identified (GenBank Accession
No.AF275549). This gene is 2.7 kb long and contains two UBA domains. It is a
new member of UBA domain protein family, encoding a putative protein of 502
amino acids with a theoretical molecular mass of 55 kD, so we have named this
gene UBAP1 for ubiquitin associated protein 1 (HUGO Gene Nomenclature
Committee-approved symbol). Northern blot and RT-PCR analysis demonstrated a
ubiquitous pattern of gene expression in human and mouse tissues. Direct
sequencing analysis of the coding region of hUBAP1 following RT-PCR
failed to reveal any mutations in a preliminary screening of NPC cell line HNE1
and primary nasopharyngeal carcinomas samples. However, more detailed analysis
is to be performed to reveal if fine mutations of this gene are present in NPC.
Key words nasopharyngeal neoplasms；gene expression；gene cloning；chromosome 9p；UBA domain
*Corresponding author：Tel, 86-731-4805383；Fax, 86-731-4805383；e-mail, [email protected]