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Updated: Jan 29, 2026

Optimization of In vitro Transcription Reaction for mRNA Production Using Chromatographic At-Line Monitoring
Published on: April 4, 2025
A convenient method to generate and maintain poly(A)-encoding DNA sequences required for in vitro transcription of
Patrick Arbuthnot1, Abdullah Ely1, Kristie Bloom1
1Wits/SAMRC Antiviral Gene Therapy Research Unit, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Private Bag 3, WITS 2050, Johannesburg, South Africa.
Abstract:
Generating mRNA in vitro to encode therapeutic or cell-modifying proteins is rapidly gaining favor. An important factor that determines efficiency of translation from in vitro transcribed mRNA is the length of the 3' poly(A) sequence. However, reproducibly generating and maintaining templates from circular plasmids to have consistent lengths of the homo poly(A) sequences is challenging. The procedure reported here entails repeated restriction digestion with type IIS enzymes, ligation and circular plasmid propagation. The homopolymeric sequence of approximately 100 bp that is generated using the method is approximately equal to the number of 3' A residues found in the mRNA of mammalian cells. Evaluating expression in vivo of a reporter transcript produced using this method showed efficient expression in vivo.
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