Study on the expression and mutation of human telomeric repeat binding factor (hTRF1) in 10 malignant hematopoietic cell lines.
OBJECTIVE
Detecting the expression and mutation of human telomeric repeat binding factor (hTRF1) in 10 malignant hematopoietic cell line cells on the base of determining its genomic structure and its four pseudogenes to clarify if hTRF1 mutation is one of the factors of the activation of telomerase.


METHODS
hTRF1cDNA sequences were obtained from GenBank, its genome structure and pseudogenes were forecasted by BLAST and other biology information programs and then testified by sequencing. Real-time RT-PCR was used to detect the expression of hTRF1mRNA in 10 cell line cells, including myelogenous leukemia cell lines K562, HL-60, U-937, NB4, THP-1, HEL and Dami; lymphoblastic leukemia cell lines 6T-CEM, Jurkat and Raji. Telomerase activities of cells were detected by using telomeric repeat amplification (TRAP)-ELISA protocol. PCR and sequencing were used to detect mutation of each exon of hTRF1 in 10 cell line cells.


RESULTS
hTRF1 gene, mapped to 8q13, was divided into 10 exons and spans 38.6 kb. Four processed pseudogenes of hTRF1 located on chromosome 13, 18, 21 and X respectively, was named as PsihTRF1-13, PsihTRF1-18, PsihTRF1-21 and PsihTRF1-X respectively. All cell line cells showed positive telomerase activity. The expression of hTRF1 was significantly lower in malignant hematopoietic cell lines cells (0.0338, 0.0108-0.0749) than in normal mononuclear cells (0.0493, 0.0369-0.128) (P=0.004). But no significant mutation was found in all exons of hTRF1 in 10 cell line cells. Four variants were found in part of intron 1, 2 and 8 of hTRF1. Their infection on gene function is unknown and needs further studies.


CONCLUSIONS
hTRF1 mutation is probably not one of the main factors for telomerase activation in malignant hematopoietic disease.
Sun
Jie
J
Department of Hematology, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China.
Huang
He
H
Zhu
Yuan-yuan
YY
Lan
Jian-ping
JP
Li
Jing-yuan
JY
Lai
Xiao-yu
XY
Yu
Jian
J
D001483:Base Sequence; D045744:Cell Line, Tumor / Q000378:metabolism; D002874:Chromosome Mapping / Q000379:methods*; D004252:DNA Mutational Analysis / Q000379:methods*; D015972:Gene Expression Regulation, Neoplastic; D020022:Genetic Predisposition to Disease / Q000235:genetics; D019337:Hematologic Neoplasms / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D000089804:Shelterin Complex; D034501:Telomere-Binding Proteins / Q000235:genetics* / Q000378:metabolism*
D000089804:Shelterin Complex; C059329:TERF1 protein, human; D034501:Telomere-Binding Proteins