Mutations in the Drosophila melanogaster gene three rows permit aspects of mitosis to continue in the absence of chromatid segregation

We have cloned the three rows (thr) gene, by a combination of chromosome microdissection and P element tagging. We describe phenotypes of embryos homozygous for mutations at the thr locus. Maternal mRNA and protein appear to be sufficient to allow 14 rounds of mitosis in embryos homozygous for thr mutations. However, a small percentage of cells in syncytial blastoderm stage thr embryos sink into the interior of the embryo as if they have failed to divide properly. Following cellularisation all cells complete mitosis 14 normally. All cells become delayed at mitosis 15 with their chromosomes remaining aligned on the spindle in a metaphase-like configuration, even though both cyclins A and B have both been degraded. As cyclin B degradation occurs at the metaphase-anaphase transition, subsequent to the microtubule integrity checkpoint, the delay induced by mutations at the thr locus defines a later point in mitotic progression. Chromosomes in the cells of thr embryos do not undertake anaphase separation, but remain at the metaphase plate. Subsequently they decondense. A subset of nuclei go on to replicate their DNA but there is no further mitotic division

Mutations in the Drosophila melanogaster gene three rows permit aspects of mitosis to continue in the absence of chromatid segregation

We have cloned the three rows (thr) gene, by a combination of chromosome microdissection and P element tagging. We describe phenotypes of embryos homozygous for mutations at the thr locus. Maternal mRNA and protein appear to be sufficient to allow 14 rounds of mitosis in embryos homozygous for thr mutations. However, a small percentage of cells in syncytial blastoderm stage thr embryos sink into the interior of the embryo as if they have failed to divide properly. Following cellularisation all cells complete mitosis 14 normally. All cells become delayed at mitosis 15 with their chromosomes remaining aligned on the spindle in a metaphase-like configuration, even though both cyclins A and B have both been degraded. As cyclin B degradation occurs at the metaphase-anaphase transition, subsequent to the microtubule integrity checkpoint, the delay induced by mutations at the thr locus defines a later point in mitotic progression. Chromosomes in the cells of thr embryos do not undertake anaphase separation, but remain at the metaphase plate. Subsequently they decondense. A subset of nuclei go on to replicate their DNA but there is no further mitotic division

Giant nuclei is essential in the cell cycle transition from meiosis to mitosis

At the transition from meiosis to cleavage mitoses, Drosophila requires the cell cycle regulators encoded by the genes, giant nuclei (gnu), plutonium (plu) and pan gu (png). Embryos lacking Gnu protein undergo DNA replication and centrosome proliferation without chromosome condensation or mitotic segregation. We have identified the gnu gene encoding a novel phosphoprotein dephosphorylated by Protein phosphatase 1 at egg activation. Gnu is normally expressed in the nurse cells and oocyte of the ovary and is degraded during the embryonic cleavage mitoses. Ovarian death and sterility result from gnu gain of function. gnu function requires the activity of pan gu and plu

The FAIR Guiding Principles for scientific data management and stewardship

There is an urgent need to improve the infrastructure supporting the reuse of scholarly data. A diverse set of stakeholders—representing academia, industry, funding agencies, and scholarly publishers—have come together to design and jointly endorse a concise and measureable set of principles that we refer to as the FAIR Data Principles. The intent is that these may act as a guideline for those wishing to enhance the reusability of their data holdings. Distinct from peer initiatives that focus on the human scholar, the FAIR Principles put specific emphasis on enhancing the ability of machines to automatically find and use the data, in addition to supporting its reuse by individuals. This Comment is the first formal publication of the FAIR Principles, and includes the rationale behind them, and some exemplar implementations in the community

Cloning and chromosomal localization of Drosophila cDNA encoding the catalytic subunit of protein phosphatase 1α. High conservation between mammalian and insect sequences

A 1.2‐kb clone containing the full coding sequence of a protein phosphatase 1 catalytic subunit has been isolated from a Drosophila head cDNA library. It encodes a polypeptide of 302 amino acids with a molecular mass of 34.5 kDa. The predicted protein sequence is 92% identical (94% similar) to rabbit protein phosphatase 1α (PP‐1α) demonstrating strict conservation of the phosphatase catalytic subunit over a considerable evolutionary distance. Abundant 1.6‐kb and 2.5‐kb mRNA transcripts were detected troughout Drosophila development. The clone hybridised to four sites on Drosophila salivary gland polytene chromosomes. The major site is at 87B6‐12 on the right arm of chromosome 3. In addition, there are three secondary sites, one on the same chromosome at 96A2‐5 and two on the X chromosome at 9C1‐2 and 13C1‐2. Isolation of a further cDNA clone, hybridising to 9C1‐2 and encoding part of the catalytic subunit 88% similar to Drosophila PP‐1α, proves the existence of at least two transcriptionally active genes for protein phosphatase 1

Cloning and chromosomal localization of Drosophila cDNA encoding the catalytic subunit of protein phosphatase 1α. High conservation between mammalian and insect sequences

A 1.2‐kb clone containing the full coding sequence of a protein phosphatase 1 catalytic subunit has been isolated from a Drosophila head cDNA library. It encodes a polypeptide of 302 amino acids with a molecular mass of 34.5 kDa. The predicted protein sequence is 92% identical (94% similar) to rabbit protein phosphatase 1α (PP‐1α) demonstrating strict conservation of the phosphatase catalytic subunit over a considerable evolutionary distance. Abundant 1.6‐kb and 2.5‐kb mRNA transcripts were detected troughout Drosophila development. The clone hybridised to four sites on Drosophila salivary gland polytene chromosomes. The major site is at 87B6‐12 on the right arm of chromosome 3. In addition, there are three secondary sites, one on the same chromosome at 96A2‐5 and two on the X chromosome at 9C1‐2 and 13C1‐2. Isolation of a further cDNA clone, hybridising to 9C1‐2 and encoding part of the catalytic subunit 88% similar to Drosophila PP‐1α, proves the existence of at least two transcriptionally active genes for protein phosphatase 1