Barbara A. Kosciolek

Human lymphocyte telomerase is genetically regulated

Research on both cancer and aging has focused attention on the regulation of telomerase, the enzyme that synthesizes the ends of chromosomal DNA. To analyze the relative importance of genetic vs. environmental factors in determining telomerase inducibility, we have compared telomerase activity in phytohemagglutinin‐stimulated peripheral blood lymphocytes from monozygotic and dizygotic twin pairs. The heritability calculated was 0.814, indicating that lymphocyte inducible telomerase activity is determined principally by genetic rather than by environmental factors. Genes Chromosomes Cancer 21:124–130, 1998.

Telomere-related components are coordinately synthesized during human T-lymphocyte activation

Since telomerase activity is present in most malignant cells, but absent in most normal cells, its induction in normal cells warrants scrutiny. Therefore we have analyzed the inducibility of telomere-related components in normal lymphocytes during their activation. Telomerase activity increased over 400-fold, telomerase reverse transcriptase (hTERT) mRNA 52 x , telomerase RNA 32 x , TTAGGG repeat binding factor 1 mRNA 19 x , TTAGGG repeat binding factor 2 mRNA 20 x , and telomerase-associated protein mRNA 17 x . The peak value for each was reached at about 72 h. However hTERT rose fastest and synchronously with telomerase activity. Thus in normal human lymphocytes (1) the syntheses of all cloned telomerase-related components are coordinately regulated and (2) hTERT may have a priming role.

Oncogene expression in neurofibromatosis.

To investigate the role of oncogenes in malignancies characteristic of neurofibromatosis, oncogene transcripts were quantitated in a neurofibrosarcoma and in control tissue from a patient with hereditary neurofibromatosis. Sis and N-ras were moderately hyperexpressed, raf, Blym, and erbA were slightly hyperexpressed, and abl, erbB, fes/fps, fgr, fos, mos, myb, myc, N-myc, rasHarvey, rasKirsten, ros, src, and yes were not hyperexpressed in the tumor compared to the control tissue. Although additional tumors will be assayed before conclusions are possible, it may be significant that the two oncogenes most hyperexpressed are prior suspects for a pathogenetic role in tumors of the nervous system.