We report the sequences of Neurospora crassa mitochondrial alanine, leucinel, leucine2, threonine, tryptophan, and valine tRNAs. On the basis of the anticodon sequences of these tRNAs and of a glutamine tRNA, whose sequence analysis is nearly complete, we infer the following: (i) The N. crassa mitochondrial tRNA species for alanine, leucine2, threonine, and valine, amino acids that belong to four-codon families (GCN, CUN, ACN, and GUN, respectively; N = U, C, A, or G) all contain an unmodified U in the first position of the anticodon. In contrast, tRNA species for glutamine, leucinel, and tryptophan, amino acids that use codons ending in purines (CAt, URJC, and UGG, respectively) contain a modified U derivative in the same position. These findings and the fact that we have not detected any other isoacceptor tRNAs for these amino acids suggest that N. crassa mitochondrial tRNAs containing U in the first position of the anticodon are capable of reading all four codons of a four-codon family whereas those containing a modified U are restricted to reading codons ending in A or G. Such an -expanded codon-reading ability of certain mitochondrial tRNAs will explain how the mitochondrial protein-synthesizing system operates with a much lower number of tRNA species than do systems present in prokaryotes or in eukaryotic cytoplasm. (ii) The anticodon sequence of the N. crassa mitochondrial tryptophan tRNA is U*CA and not CCA or CmCA as is the case with tryptophan tRNAs from prokaryotes or from eukaryotic cytoplasm. Because a tRNA with U*CA in the anticodon would be expected to read the codon UGA, as well as the normal tryptophan codon UGG, this suggests that in N. crassa mitochondria, as in yeast and in human mitochondria, UGA is a codon for tryptophan and not a signal for chain termination. (iii) The anticodon sequences of the two leucine tRNAs indicate that N. crassa mitochondria use both families of leucine codons (UUA and CUN; N = U, C, A, or G) for leucine, in contrast to yeast mitochondria [Li, M. & Tzagoloff, A. (1979) Cell 18, 47-53] in which the CUA leucine codon and possibly the entire CUN family of leucine codons may be translated as threonine.Mitochondria exist within the cytoplasm of eukaryotic cells (1). They contain a DNA genome and a protein-synthesizing system that is distinct from the system in the cytoplasm (2, 3). Virtually all of the protein components of the mitochondrial protein biosynthetic machinery are coded for by the nuclear DNA, made in the cytoplasm, and imported into the mitochondria. In contrast, it appears that all the RNAs necessary for mitochondrial protein synthesis (ribosomal, transfer, messenger) are made inside the mitochondrion. Although the sizes of mitochondrial DNAs from different sources vary, in all cases the mitochondrial DNA codes for [8][9][10][11][12] proteins, at least two ribosomal RNAs, and several tRNAs (2, 3).A puzzling observation until now has been that the number of different tRNA species present in fungal (4, 5), amphibian (6), and mammalian (7) mitocho...

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Governance of solar geoengineering is important and challenging, with particular concern arising from commercial actors’ involvement. Policies relating to intellectual property, including patents and trade secrets, and to data access will shape private actors’ behavior and regulate access to data and technologies. There has been little careful consideration of the possible roles of and interrelationships among commercial actors, intellectual property, and intellectual property policy. Despite the current low level of commercial activity and intellectual property rights in this domain, we expect both to grow as research and development continue. Given the public good nature of solar geoengineering, the relationship between the public and private sectors would likely assume a procurement structure. Innovative policy approaches to intellectual property and data access that are specific to solar geoengineering are warranted. These current circumstances also present opportunities for the development of policy and norms that might soon be lost. We consider some possible approaches, and recommend a bottom‐up, primarily nonstate, voluntary “research commons” for patents and data that are related to solar geoengineering. This would facilitate information sharing and limit data fragmentation and trade secrecy. It would also provide an incentive for commons members to pledge to limit some forms of intellectual property acquisition and to assure access on reasonable terms, thereby limiting the need for enforcement. This should help reduce downstream barriers to innovation and to encourage the potential development of technologies at reasonable cost. Such a research commons might also catalyze the adoption of best practices in research and development. This article is categorized under: Policy and Governance > Private Governance of Climate Change Social Status of Climate Change Knowledge > Knowledge and Practice

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