Transcriptions of the Bacteriophage T4 Template in Vitro: Separation of „Delayed Early” from „Immediate Early” Transcription*
Abstract
The synthesis of different early T4 transcripts by E. coli RNA polymerase in vitro can be dissociated in two ways: (1) when T4 DNA is mechanically degraded, it selectively loses the ability to serve as a template for the transcription of delayed early T4 RNA; (2) when initiation of RNA synthesis on intact T4 DNA is limited to a very short time interval immediate early T4 RNA is synthesized at once but delayed early polynucleotide sequences appear only after a time lag. We conclude that initiation sites for T4 early RNA synthesis are closer to immediate early than to delayed early segments of the T4 template and that immediate early and delayed early segments of the T4 chromosome are interspersed. We propose that this interspersing is significant for the programming of transcription during T4 development.
Footnotes
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↵ † Present address: Instituto di Genetica, Universita di Pavia, Pavia, Italy.
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↵ ‡ Present address: Istitut de Biologie Moléculaire, Université de Genève, Geneva, Switzerland.
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↵ * This work was supported by grants from the National Institutes of Child Health and Human Development (HD 01257) and General Medical Sciences (GM 15880). E. N. B. gratefully acknowledges a postdoctoral fellowship of the National Science Foundation, O. G. acknowledges a postdoctoral fellowship from the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina, and E. P. G. acknowledges a Research Career Development Award from the U.S. Public Health Service.
