Genetics, Vol. 174, September 2006, Copyright © 2006

Issue Highlights

Introns regulate RNA and protein abundance in yeast, pp. 511–518

Kara Juneau, Molly Miranda, Maureen E. Hillenmeyer, Corey Nislow and Ronald W. Davis

The purpose of introns in the architecturally simple genome of yeast is not well understood. However, intron-containing genes are shown to produce both more RNA and more protein. They are also more likely to be haplo-insufficient than are nonintronic genes. The deletion of introns from three essential genes decreased cellular RNA levels and caused measurable growth defects. These data provide strong evidence that the presence of introns improves transcriptional and translational yield.

Drosophila Reptin and other TIP60 complex components promote generation of silent chromatin, pp. 241–251

Dai Qi, Haining Jin, Tobias Lilja and Mattias Mannervik

Reptin, a component of the TIP60 complex, is shown to play a critical role in the control of heterochromatic gene silencing. The TIP60 complex contains a histone acetyltransferase (HAT) activity, generally thought to be involved in gene activation. However, these results suggest that HAT function can also play a role in gene silencing.

Different mating-type-regulated genes affect the DNA repair defects of Saccharomyces RAD51, RAD52 and RAD55 mutants, pp. 41–55

Maria Valencia-Burton, Masaya Oki, Jean Johnson, Tracey A. Seier, Rohinton Kamakaka and James E. Haber

Mating-type heterozygosity is shown to partially suppress the repair defects exhibited by mutations in four genes: RAD55, RAD57, RAD51, and RAD52. In the case of rad55 mutants, the basis for the suppression of the repair defect appears to reflect the downregulation of the deleting genes required for non-homologous end-joining, a process that is repressed in MATa/MAT{alpha} cells.

Novel role for checkpoint Rad53 protein kinase in the initiation of chromosomal DNA replication in Saccharomyces cerevisiae, pp. 87–99

Paul R. Dohrmann and Robert A. Sclafani

This elegant genetic study provides the best evidence to date that Rad53p is involved in replication initiation. Rad53's role in replication is independent of both DNA and mitotic checkpoints. However, the requirement for Rad53 can be suppressed by the deletion of the major histone H3/H4 gene pair, indicating that Rad53 may be regulating initiation by controlling histone protein levels and/or by affecting origin chromatin structure.

The mechanism of secondary nondisjunction in Drosophila melanogaster females, pp. 67–78

Youbin Xiang and R. Scott Hawley

In the first paper ever published in this journal, Calvin Bridges noted that nonexchange X chromosomes segregate from the Y chromosome in XXY females, a process he named "secondary nondisjunction." These XX {longleftrightarrow} Y segregations are presaged by early heterochromatic associations that create an X-Y-X trivalent. However, this trivalent is maintained only if the X chromosomes fail to crossover. The dissolution of the trivalent in oocytes with crossover X chromosomes demonstrates that exchanges can alter centromeric associations during meiotic prophase.

The meiotic bouquet promotes homolog interactions and restricts ectopic recombination in Schizosaccharomyces pombe, pp. 167–177

Luther Davis and Gerald R. Smith

The telomere bouquet of Schizosaccharomyces pombe promotes allelic recombination and restricts ectopic recombination. In addition, Bqt2, a meiosis-specific protein required for bouquet formation, is required for wild-type levels of homolog pairing and meiotic allelic recombination. Finally, and perhaps most intriguingly, while both the bouquet and nuclear movement promote pairing, only the bouquet restricts ectopic recombination.

Quantitative trait loci for locomotor behavior in Drosophila melanogaster, pp. 271–284

Katherine W. Jordan, Theodore J. Morgan and Trudy F. C. Mackay

Quantitative trait loci (QTL) mapping and the quantitative complementation test have identified 13 candidate genes affecting locomotor reactivity in Drosophila, including the Dopa decarboxylase (Ddc) gene. Linkage disequilibrium mapping showed that polymorphisms at Ddc were associated with naturally occurring genetic variation in locomotor behavior. These data implicate variation in the synthesis of bioamines as a factor contributing to natural variation in locomotor reactivity.


Related articles in Genetics:

The Meiotic Bouquet Promotes Homolog Interactions and Restricts Ectopic Recombination in Schizosaccharomyces pombe
Luther Davis and Gerald R. Smith
Genetics 2006 174: 167-177. [Abstract] [Full Text]  

Drosophila Reptin and Other TIP60 Complex Components Promote Generation of Silent Chromatin
Dai Qi, Haining Jin, Tobias Lilja, and Mattias Mannervik
Genetics 2006 174: 241-251. [Abstract] [Full Text]  

Quantitative Trait Loci for Locomotor Behavior in Drosophila melanogaster
Katherine W. Jordan, Theodore J. Morgan, and Trudy F. C. Mackay
Genetics 2006 174: 271-284. [Abstract] [Full Text]  

Different Mating-Type-Regulated Genes Affect the DNA Repair Defects of Saccharomyces RAD51, RAD52 and RAD55 Mutants
Maria Valencia-Burton, Masaya Oki, Jean Johnson, Tracey A. Seier, Rohinton Kamakaka, and James E. Haber
Genetics 2006 174: 41-55. [Abstract] [Full Text]  

Introns Regulate RNA and Protein Abundance in Yeast
Kara Juneau, Molly Miranda, Maureen E. Hillenmeyer, Corey Nislow, and Ronald W. Davis
Genetics 2006 174: 511-518. [Abstract] [Full Text]  

The Mechanism of Secondary Nondisjunction in Drosophila melanogaster Females
Youbin Xiang and R. Scott Hawley
Genetics 2006 174: 67-78. [Abstract] [Full Text]  

Novel Role for Checkpoint Rad53 Protein Kinase in the Initiation of Chromosomal DNA Replication in Saccharomyces cerevisiae
Paul R. Dohrmann and Robert A. Sclafani
Genetics 2006 174: 87-99. [Abstract] [Full Text]