Expression of either the TCL1 oncogene, or transcripts from its homologue MTCP1/c6.1B, in leukaemic and non-leukaemic T cells from ataxia telangiectasia patients.
Patients with the recessively inherited disorder ataxia telangiectasia (A-T) have a high level of specific chromosome translocations which can be easily observed in peripheral T cells and show a greatly increased predisposition to leukaemia/lymphoma, mainly of T cell origin. Some translocation cells proliferate into a large clone and may develop into T cell prolymphocytic leukaemia (T-PLL). By the time of diagnosis of T-PLL, the clone contains many more genetic changes in the form of additional translocations. T-PLL is also seen in non-A-T individuals where expression of either TCL1 (at 14q32) or the c6.1B/MTCP1 A1 transcript (at-Xq28) has been demonstrated in just a few instances. We show here, that expression of TCL1 occurs in leukaemic T cells from A-T patients with chromosome 14 rearrangements. Expression of TCL1 also occurs in the preleukaemic clone cells of A-T patients containing the primary translocation alone. Some expression of TCL1 could also be detected in randomly selected A-T patients without large cytogenetic clones and without any evidence of leukaemic change. We also show that expression of the B1 transcript from a second gene, MTCP1, occurred at a relatively high level only in two T-PLL tumours from A-T patients with t(X;14) translocations whereas the MTCP1/A1 transcript is much more widely expressed in both tumour and non tumour cells of A-T and non-A-T individuals.
Thick
J
J
Institute for Cancer Studies, Medical School, University of Birmingham, UK.
Metcalfe
J A
JA
Mak
Y F
YF
Beatty
D
D
Minegishi
M
M
Dyer
M J
MJ
Lucas
G
G
Taylor
A M
AM
D001260:Ataxia Telangiectasia / Q000235:genetics*; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000235:genetics*; D006801:Humans; D015463:Leukemia, Prolymphocytic / Q000235:genetics*; D008969:Molecular Sequence Data; D009857:Oncogenes; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger / Q000032:analysis*; D013601:T-Lymphocytes / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics*; D014178:Translocation, Genetic
D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; C090851:TCL1A protein, human; D014157:Transcription Factors