Advances in gene technology : molecular biology of the immune system proceedings of the Seventeenth Miami Winter Symposium, Miami, Florida, U.S.A., February 11-15, 1985 / edited by J. Wayne Streilein [and others].

  • Miami Winter Symposium
Date:
1985
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Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: Advances in gene technology : molecular biology of the immune system proceedings of the Seventeenth Miami Winter Symposium, Miami, Florida, U.S.A., February 11-15, 1985 / edited by J. Wayne Streilein [and others]. Source: Wellcome Collection.

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    353 REGULATION OF IgD SYNTHESIS IN MURINE NEONATAL В LYMPHOCYTES Dorothy Yuan Dept. of Pathology, U.T, Health Science Center at Dallas, Dallas, Texas, 75235. We have previously shown, by means of in vitro nascent RNA chain elongation studies, that in adult В lymphocytes the transcriptional activity across the Cy gene is 2 to 3 fold higher than that of the C6 gene (1). The same relative transcriptional activity of Cy and Cô is maintained in neonatal В lymphocytes (1) despite the fact that IgD is expressed at a much lower density (approx. 20% of adult levels) on the cell surface. In order to ascertain that the transcriptional activities we measure in neonatal lymphocytes are not due to selective labeling of a minor population of cells expressing high densities of membrane IgD, the transcriptional profile of 2-day neonates was also determined. Fig. 1 shows that although these cells express no detectable IgD on their surfaces (2), the relative transcriptional activity of the С6 gene is still 1/3 to 1/2 that of the Cy gene. Fig. 1. Transcription of the y-6 gene complex in neonatal В lymphocytes. Nuclei from 3-4 x 10^ total spleen cells from d-2 Balb/C neonates ^ were labeled with 500 yCi of [32p] u,jp ^2 min. RNA was extracted and hybrid¬ ized to the DNA probes shown at the bottom of the figure. Relative incor¬ poration per base was determined from densitome¬ ter tracings of the autora- diographs as described (1). The results presented represent the average of 2 experiments. In order to detect a possible defect in processing of 6mRNA in neonatal lymphocytes, the steady state concentration of ômRNA was measured and compared to that in adult lymphocytes by slot blot analysis. Total poly A+ RNA from both sources was immobilized on nitrocellulose filters in graded concentrations, and subsequently hybridized to ^^P labeled DNA probes containing sequences for either C6 or ym. It was found that if the relative amount of C6 to ym hybridization in RNA from adult lymphocytes is normalized to 1, the relative amount of С б to ym hybridization in RNA from neonatal lymphocytes is approximately 1/2. These Ш СЛ < Ш tr LÜ Û. < a; 0 01 (Г О О ш 1 > ш ее С8 мм s X »г
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