Molecular cloning of TA16, a transcriptional repressor that may mediate glucocorticoid-induced growth arrest of leiomyosarcoma cells.
The DDT1 MF2 smooth muscle tumor cell line was derived from an estrogen/androgen-induced leiomyosarcoma that arose in the ductus deferens of a Syrian hamster. The growth of this cell line is arrested at the G0/G1 phase of the cell cycle after treatment with glucocorticoids. To identify the putative gene(s) that are potentially involved in this hormone-induced cell growth arrest, we have used a differential screening technique to clone those genes whose expression is induced or up-regulated by glucocorticoids. A number of glucocorticoid response genes were thereby isolated from the leiomyosarcoma cells. One of these clones, termed TA16, was found to be markedly up-regulated by glucocorticoids in DDT1 MF2 cells, but only marginally changed in GR1 cells, a glucocorticoid-resistant variant that was selected from the wild type DDT1 MF2 cell. Isolation and sequencing of its intact cDNA indicated that the TA16 encodes a protein 485 amino acids long, and its sequence is closely homologous to a novel transcriptional repressor that presumably represses the transcription activity of some zinc finger transcriptional factors through a direct interaction. Transfection assays demonstrated that introduction of an antisense TA16 cDNA expression vector, controlled by an MMTV promoter, into the DDT1 MF2 cell significantly relieved the glucocorticoid-induced cell growth arrest. This finding suggests that TA16 might participate in the mediation of glucocorticoid-induced cell cycle arrest in leiomyosarcoma cells.
Fan
W
W
Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston 29425, USA.
Ma
J X
JX
Cheng
L
L
Norris
J S
JS
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002455:Cell Division / Q000187:drug effects / Q000235:genetics; D003001:Cloning, Molecular; D006224:Cricetinae; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D005938:Glucocorticoids / Q000494:pharmacology*; D006801:Humans; D007890:Leiomyosarcoma / Q000188:drug therapy / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D016376:Oligonucleotides, Antisense; D016133:Polymerase Chain Reaction / Q000379:methods; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D014157:Transcription Factors; D014162:Transfection; D014407:Tumor Cells, Cultured
D005938:Glucocorticoids; C094815:NAB1 protein, human; C490624:Nab1 protein, mouse; C490623:Nab1 protein, rat; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; D012097:Repressor Proteins; C108210:TA16 protein, Mesocricetus auratus; D014157:Transcription Factors