DNA Supply Chain (image) Massachusetts Institute of Technology Share Print E-Mail Caption The regulation of the enzyme ribonucleotide reductase allows for just the right levels of deoxynucleotides, the building blocks of DNA, to be produced in the cell. Credit Christina Zimanyi, Percival Yang-Ting Chen, and Catherine Drennan Usage Restrictions MIT images are made available to non-commercial entities, press and the general public under a Creative Commons Attribution Non-Commercial No Derivatives license. You may not alter the images provided, other than to crop them to size. A credit line must be used when reproducing images. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.