We show that a functional component of the C. elegans mitotic machinery regulates X chromosome gene expression. This protein, MIX-1, is a member of the dosage compensation complex that associates specifically with hermaphrodite X chromosomes to reduce their gene expression during interphase. MIX-1 also associates with all mitotic chromosomes to ensure their proper segregation. Both dosage compe...

In many diploid species, sex determination is linked to a pair of sex chromosomes that evolved from a pair of autosomes. In theseorganisms, thedegenerationof thesex-limitedYorWchromosomecausesa reduction ingenedose in theheterogametic sex forX-orZ-linked genes. Variations in gene dose are detrimental for large chromosomal regions when they span dosage-sensitive genes, andmany organi...

Some insight into the developmental basis for imprinting specific genes during the evolution of mammals can be gained from conventional gene 'knockout' studies. However, the consequences of full loss of function are often wide-ranging and may obscure the critical, dosage-related phenotype. This review focuses on transgenic techniques employed to alter the dosage of imprinted genes, including th...

Gene-specific and chromosome-wide mechanisms of transcriptional regulation control development in multicellular organisms. SDC-2, the determinant of hermaphrodite fate in Caenorhabditis elegans, is a paradigm for both modes of regulation. SDC-2 represses transcription of X chromosomes to achieve dosage compensation, and it also represses the male sex-determination gene her-1 to elicit hermaphro...

In Drosophila melanogaster the male specific lethal (MSL) complex is required for upregulation of expression of most X-linked genes in males, thereby achieving X chromosome dosage compensation. The MSL complex is highly enriched across most active X-linked genes with a bias towards the 3' end. Previous studies have shown that gene transcription facilitates MSL complex binding but the type of pr...

We would like to reply Yang et al., 2020, reporting a patient diagnosed with progressive supranuclear palsy (PSP) who carried two novel heterozygous missense variants in GRN gene. The case reported by raises some concerns. In summary, the study of reports PSP-like phenotype patients carrying gene, putatively compound heterozygous. Finally, we suggest that further analyses (including segregation...

One of the most extreme examples of gene dosage sensitivity is the Triplo-lethal locus (Tpl) on the third chromosome of Drosophila melanogaster, which is lethal when present in either one or three copies. Increased dosage of an unlinked locus, Isis, suppresses the triplo-lethal phenotype of Tpl, but not the haplo-lethal phenotype. We have mapped Isis to the X chromosome region 7E3-8A5, and show...

The bidirectional replication of bacterial genomes leads to transient gene dosage effects. Here, we show that such effects shape the chromosome organisation of fast-growing bacteria and that they correlate strongly with maximal growth rate. Surprisingly the predicted maximal number of replication rounds shows little if any phylogenetic inertia, suggesting that it is a very labile trait. Yet, a ...