Ishiguro A, Spirin K, Shiohara M, Tobler A, Norton J D, Rigolet M, Shimbo T, Koeffler H P
Department of Medicine, Cedars-Sinai Medical Center, UCLA School of Medicine 90048, USA.
Leuk Res. 1995 Dec;19(12):989-96. doi: 10.1016/0145-2126(95)00084-4.
Helix-loop-helix (HLH) transcription factors are involved in cellular growth and differentiation. The Id (inhibitor of DNA binding and differentiation) HLH proteins, in a dominantly negative fashion, regulate transcriptional activities of basic HLH proteins. We examined by northern hybridization the expression of Id2 and Id3 mRNA in human leukemia/lymphoma lines and patient samples, as well as resting and activated normal human lymphocytes from peripheral blood (PBL). The Id2 mRNA was abundantly expressed in 5/12 T-cell and 3/4 B-cell lines, and Id3 mRNA was detected in 4/12 T-cell and 3/4 B-cell lines. Interestingly, Id2, but not Id3, mRNA was strongly expressed in 4/5 T-cell lines infected with human T-cell leukemia virus type I (HTLV-I) (ATL-1k, MT-2, S-LB1) and type II (Mo). Another unexpected finding was that T-cell leukemias and T-cell lines often expressed either Id2 or Id3 mRNA. In addition, resting PBL constitutively expressed prominent levels of Id2 mRNA, but not Id3 mRNA. Upon PHA-stimulation, Id2 expression decreased and Id3 levels increased with biphasic kinetics. Taken together, our studies revealed three unexpected findings which require further analysis: (1) expression of Id2 mRNA is often associated with lymphocytic transformation by HTLV-I or -II; (2) T-cells usually express either Id2 or Id3 mRNA, but B-cells often express both simultaneously; (3) non-dividing, normal PBL express high levels of Id2 and no Id3 mRNA; and with the onset of cellular proliferation, levels of Id2 mRNA decrease while levels of Id3 mRNA increase, suggesting that regulation of expression of these closely related genes is disparate.
螺旋-环-螺旋（HLH）转录因子参与细胞生长和分化。Id（DNA结合和分化抑制因子）HLH蛋白以显性负性方式调节碱性HLH蛋白的转录活性。我们通过Northern杂交检测了Id2和Id3 mRNA在人白血病/淋巴瘤细胞系和患者样本以及外周血（PBL）中静息和活化的正常人淋巴细胞中的表达。Id2 mRNA在5/12个T细胞系和3/4个B细胞系中大量表达，Id3 mRNA在4/12个T细胞系和3/4个B细胞系中被检测到。有趣的是，Id2而非Id3 mRNA在感染I型（HTLV-I）（ATL-1k、MT-2、S-LB1）和II型（Mo）人T细胞白血病病毒的4/5个T细胞系中强烈表达。另一个意外发现是，T细胞白血病和T细胞系通常只表达Id2或Id3 mRNA。此外，静息PBL组成性表达显著水平的Id2 mRNA，但不表达Id3 mRNA。经PHA刺激后，Id2表达下降，Id3水平呈双相动力学增加。综上所述，我们的研究揭示了三个需要进一步分析的意外发现：（1）Id2 mRNA的表达常与HTLV-I或-II介导的淋巴细胞转化相关；（2）T细胞通常只表达Id2或Id3 mRNA，但B细胞常同时表达两者；（3）未分裂的正常PBL表达高水平的Id2且不表达Id3 mRNA；随着细胞增殖的开始，Id2 mRNA水平下降而Id3 mRNA水平增加，这表明这些密切相关基因的表达调控是不同的。
