76.
HYPOXIA INDUCIBLE FACTOR-1 MAY BE A REGULATOR OF BAX GENE
EXPRESSION IN VITRO. Xin Hong
1
, Zhonghai Xiao
1
, Zhaoyun Yin
1
, Xuetao Pei
2
. Tianjin
Institute of Health and Environmental Medicine, Tianjin
1
, Beijing Institute of Transfusion
Medicine, Beijing
2
.
To investigate the mechanisms by which HIF-1 regulates bax gene expression, the bax 5`
untranscription domain (UTD) was molecularly cloned with PCR from human genomic DNA and
was determined with restriction enzymes and sequence analysis. Then the bax 5` UTD was sub-
cloned to the reporter gene vector (pGL3-Basic vector). The bax 5` UTD pGL3-Basicvector
(pGL3- bax5') was transfected into HepG2 cells with or without HIF-1_ expression vector, and
also the antisense p53 vector was co-transfected with those two vectors during hypoxia and
normoxia. The molecularly cloned bax 5'UTD gene sequence has 100% homology with the
sequence in the gene bank. PCR analysis revealed that the bax 5` UTD was corrective connected
to the pGL3-Basic reporter gene vector. Based on the cis-acting element of the hypoxic sensitive
genes that has been reported as the site of HIF-1 binding and mediating the genes' expression,
four potential motifs that could be the HIF-1 binding site were identified in the bax 5'UTD via
analysis of the bax 5'UTD sequence. Under normoxic conditions, the expression of the reporter
gene increased in the HIF-1_ transfected cells. The increment of the expression was partly
abolished when co-transfecting antisense p53 vector. Under hypoxic condition, the stress of
hypoxia alone without any other vector transfected could induce the expression of reporter gene.
In addition, the expression of the reporter gene in other transfected cells was also increased, but
the degree of the increment was more significant than observed under normoxic conditions.
Conclusions: HIF-1 could regulate bax gene expression under hypoxic conditions a process in
which p53 could also participate. This work was supported by grants from national science funds
(30393134 and 30170354)
77.
EFFECTS OF IPTAKALIM ON MRNA LEVEL OF ATP-SENSITIVE POTASSIUM
CHANNELS OF PULMONARY ARTERY SMOOTH MUSCLE CELLS IN CHRONICALLY
HYPOXIC RATS. Wang Hong
1
, Shen Hong
1
, Xie Weiping
2
, Hu Gang
3
. Department of
Pharmacology & Neurobiology, Nanjing Medical University
1
, Department of Pulmonology of
First Affiliated Hospital, Nanjing Medical University, Nanjing China
2
, Department of
Pharmacology & Neurobiology, Nanjing Medical University, Nanjing, Chian
3
.
Objectives To investigate the mRNA expression of ATP-sensitive potassium (KATP)
channels of the main pulmonary artery in rats with chronic hypoxic pulmonary artery
hypertension (CHPAH) and the effect of the novel KATP opener Iptakalim on the mRNA
expression of KATP channels. Methods Sixteen Sprague-Dawley(SD) male rats were randomly
assigned into either a control group, an hypoxic group, a low dose Iptakalim group (0.75mg·kg-
1·d-1), or a high dose Iptakalim group (1.5mg·kg-1·d-1). Except for the first group, the other three
groups were put into a normobaric hypoxic chamber (10%±0.5% O2, 8h/day and 6day/week) to
establish a rat model with CHPAH. Four weeks later, reverse transcription polymerase chain
reaction (RT-PCR) was performed to analyze the mRNA level of KATP channels in main
pulmonary artery smooth muscle cells in semiquantitative manner. Results The expression of
Kir6.1, Kir6.2, SUR1 and SUR2 genes could be detected in the pulmonary artery smooth muscle
cells of normal rats, with the expression of Kir6.1 and SUR2 being greatest. The mRNA level of
SUR2 in the hypoxic group was significant lower than that in the control group (P<0.01). Chronic
iptakalim treatment could reverse these changes completely. However, there was no difference in
Kir6.1 mRNA levels among the four groups. Conclusions KATP channel transcriptional
expression was inhibited by chronic hypoxia.
78.
SEQUENCE ANALYSIS OF THE GLOBIN CDNA IN TIBETANS LIVING AT HIGH
ALTITUDE. Dong Hong-Bin
1
, Hong Xin
1
, Yin Zhao-Yun
1
. Institute of Hygiene and
Environmental Medicine, Tianjin, China
1
.
