Jerzy Dobrzelewski, Zofia Milewska and Henryk Panusz
Department of Biochemistry, Institute of Physiology and Biochemistry, Medical School; Lindleya 6, 90-131 Lodz, Poland.
1. Two low-molecular-weight nuclear RNA fractions were isolated from
the loosely-bound non-histone proteins of calf thymus chromatin: RNA I
(of 4 - 5.5S, heterogenous on polyacrylamide -gel electrophoresis), and
RNA IV (of about 3S).
2. Under the reinitiation conditions, RNA I stimulates about 2.5-fold
the template properties of homologous chromatin with bacterial polymerase,
while RNA IV inhibits these properties by about 50%.
3. When reinitiation is blocked, RNA I stimulates both the initiation
and elongation steps (by 20-30% and 60%, respectively).
4. The two fractions equally inhibit transcription (by 30-35%) with
free homologous DNA as a template.
A preliminary account of this work has been presented (J. Dobrzelewski, Z. Milewska & H. Panusz, 1978, 12th FEBS Meeting, Dresden, abstr. no. 1131).
1. Frenster JH, "Nuclear Polyanions as De-Repressors of Synthesis of Ribonucleic Acid", Nature 1965, 206: 680-683 (May 15, 1965).
2. Frenster JH, "Activation of DNA Transcription within Repressed
Chromatin by Nuclear RNA Species",
May 30, 2001, 6th Annual Meeting, The RNA
Society, Banff, Alberta, Canada, abstr. no. 237.