Neuronal differentiation of NT2/D1 teratocarcinoma cells is accompanied bya loss of lamin A/C expression and an increase in lamin B1 expression

Nuclear lamins are prominent elements of the nuclear matrix and are express ed in cell type-specific and differentiation state-specific patterns. A few observations have indicated that nervous tissue may display unusual patter ns of lamin expression, in that same neurons appear to lack A-type lamins, which are generally prominently expressed in terminally differentiated, pos tmitotic cells. To investigate lamin expression patterns during the differe ntiation of a teratocarcinoma cell line into neurons, NTS/D1 cells were ind uced to differentiate with retinoic acid treatment. Lamin expression and or ganization during differentiation in vitro were examined by quantitative im munofluorescence and immunoblotting methods. Undifferentiated NT2/D1 cells were all strongly labeled with an anti-lamin B1 antibody, but displayed mar ked variation in A/C lamin immunoreactivity. After differentiation, neurona l nuclear envelopes were significantly more strongly labeled by anti-lamin B1 antibody than those of undifferentiated cells, but completely lacked A/C lamin immunoreactivity. In contrast, nonneuronal cells displayed a slight reduction in B1 lamin immunoreactivity, along with a distinct increase in A /C lamin levels. The loss of lamin A/C expression in NT2/D1 neurons is cont rary to the pattern normally observed in most somatic cell types during ear ly development and indicates that the nuclear matrix of some neurons, along with certain neuroendocrine and hematopoietic cells, is uniquely specializ ed in this regard. (C) 1999 Academic Press.