Analysis of plasmacytoma nonhistone chromatin proteins

Ceil Biology

ANALYSIS JOHN C. Western

International

OF

Reports, Vol. 4, No. 8, August

PLASMACYTOMA

LINCOLN Infirmary,

& DAVID Glasgow

NONHISTONE I. Gil

STOTT, 6NT,

Nonhistone chromatin proteins (NHCP) are believed to be involved in the control of gene expression. Investigation has shown that many of these proteins are species and tissue specific. We have investigated subclones of an IgA producing cell line which are impaired in immunoglobulin production. It is hoped to correlate differences in the NHCP patterns with altered expression of ixnmunoglobulin genes. Nuclear protein fractions from these cell lines were analysed by 2 dimensional gel electrophoresis followed by fluorography. Individual proteins on d by their the 2-D gel are designat 9 co-ordinates of pi/M 10 . The Z-D gel patter% show qualitative and quantitative differences betIn particular proween cell lines. teins 5.2155 and 6.4127 are present in MOPC 315.40 (IgA producer) but

CHROMATJN

651/60/060605-01/$02.00/0

805

PROTEINS.

Dept. Bacteriology Scotland.

& Immunology,

absent in 315.32 (&chain producer)and preliminary results also indicate th2ey are missing in 315.35 and 315.36 (non producers). There are also quantitative differences in other proteins for example 5.3/38 which is much more intensely labelled in 315. 32 than in 315.40. The pulse chase experiments also indicate that there are turnover differences between the cell lines. The 2-D gel electrophoresis technique provides a powerful means of analysing the complex mixture of proteins that is found in eukaryotic cell nuclei. By this method it seems that most proteins are co-on to all the cell lines studied. The differences between the cell lines may be due to differences in gene expression or to the loss of chromosomes which occurs in transformed cell lines. Further work is needed to investigate the nature of these differences.

Fig. 1. Fluorograph of Plasmacytoma NHCP, labelled methionine and analysed by 2-D gel electrophoresis. a MOF’C 315.40 b MOPC 315.52

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