RNA processing in Neurospora crassa mitochondria: use of transfer RNA sequences as signals.

Formation of Mitochondria in Neurospora Crassa

The choline concentration used in the growth medium influences the density of mitochondria produced by the chol-1 mutant of Neurospora. Isopycnic centrifugation in sucrose gradients can be used to determine the density of mitochondria, and can resolve into two populations, mitochondria derived from a mixture of cells grown at low (1 microg/ml choline chloride) and high (10 microg/ml choline chl...

Interesting and unusual features in the sequence of Neurospora crassa mitochondrial tyrosine transfer RNA.

The mitochondrial tyrosine tRNA from Neurospora crassa has been sequenced and found to have several interesting features: (i) It resembles prokaryotic rather than eukaryotic tyrosine tRNAs in that it possesses a large variable loop (loop III); moreover, it can be quantitatively aminoacylated by Escherichia coli tyrosyl-tRNA synthetase but not by yeast tyrosyl-tRNA synthetase. (ii) This tRNA dif...

Formation of Mitochondria in Neurospora Crassa

Cells of a choline-requiring mutant of Neurospora crassa, labeled with radioactive choline, were transferred to unlabeled medium. At various times during their subsequent logarithmic growth, a highly purified mitochondrial fraction was prepared by sucrose density gradient centrifugation, and the distribution of label among individual mitochondria was determined by quantitative autoradiography. ...

A naturally occurring DNA-RNA complex from Neurospora crassa.

Transfer RNA methylating activity of yeast mitochondria.

Mitochondria isolated from Saccharomyces cerevisiae and purified in Urografin or sucrose gradient contain tRNA methylating activity with specificities different from those of the cytoplasm. The main reaction product, using E.coli tRNA as methyl group acceptor, is N(2),-N(2)-dimethylguanine. The corresponding mitochondrial methylase is coded by nuclear DNA. A DNA methylating activity is also ass...