A second polymorphic lens crystallin (LEN-2) in the mouse: genetic and biochemical analysis of LEN-1 and LEN-2.

Two electrophoretic polymorphisms affecting lens crystallins, designated LEN-1 and LEN-2, have been discovered among inbred strains of mice. Analysis by isoelectric focusing demonstrated that both crystallins are monomeric proteins with isoelectric points at or above pH 7. Both proteins eluted in the low molecular weight (LM) fraction upon Sephadex G-200 gel filtration but LEN-2 was shown to be larger than LEN-1 by G75SF gel filtration and denaturing gel electrophoresis.

Analysis of a mouse alpha-globin gene mutation induced by ethylnitrosourea.

A DBA/2 mouse treated with ethylnitrosourea sired an offspring whose hemoglobin showed an extra band following starch gel electrophoresis. The variant hemoglobin migrated to a more cathodal position in starch gel. Isoelectric focusing indicated that chain 5 of the mutant hemoglobin migrated to a more cathodal position than the normal chain 5 from DBA/2 mice and that the other alpha-globin, chain 1, was not affected.

The primary structure of genetic variants of mouse hemoglobin.

The primary structures of the alpha globins from CE/J, DBA/2J, and a stock of Potter's mice were determined to identify the amino acid substitutions associated with the unique isoelectric focusing patterns of these hemoglobins. In addition, the primary structures of the alpha globins from MOL III and PERU mice were studied in search of amino acid substitutions that may not be detected by isoelectric focusing. CE/J hemoglobin contains a unique kind of alpha globin called chain 5.

Differential association of transfer RNAs with the genomes of murine, feline and primate retroviruses.

The tRNAs that are bound to the genomic RNAs of several murine, feline, and primate retroviruses have been identified. Transfer RNAs were divided into those loosely bound and those tightly bound by stepwise thermal dissociation of the 70 S RNA. They were then identified and semiquantitated by aminoacylation.

Species comparison of protein synthesis accuracy.

The average accuracy of protein synthesis in reticulocytes from several mammalian species does not correlate with longevity potential from 13 to 90 years. Isoleucine incorporation into highly purified hemoglobin chains which contain no genetically coded isoleucine was used as a direct test of protein synthesis accuracy. Since isoleucine can be incorporated into these molecules by mutations in a few cells as well as errors in most cells, the constant level of isoleucine substitution may also show that the mutation rates are not dramatically different among these species.