A fetus with recombinant of chromosome 8 inherited from her carrier father

Summary A pericentric inversion of chromosome 8, inv(8)(p23q22), in a male carrier resulted in an unbalanced recombinant, rec(8)dup q, inv(8)(p23q22), which was diagnosed prenatally. The features seen in the aborted fetus resembled the features seen in a previously affected child who received the identical recombinant from her carrier mother. In this particular inversion involving chromosome 8, both male and female carriers risk producing an unbalanced progeny. Different familial pericentric inversions are reviewed for the presence or absence of unbalanced recombinants.     

Isolation and characterization of glucose derepressed invertase mutants from Schizosaccharomyces pombe

We have isolated 14 different Schizosaccharomyces pombe mutants that synthesize invertase enzyme constitutively. Analyses of invertase activities revealed that the degrees of resistance to glucose repression were not similar among different complementation groups. One of the complementation groups appeared to be associated with functional and/or regulatory defects in hexose transport. Another complementation group appeared to be specific for the regulation of the inv1 gene alone, implying that these mutations might be associated with different genes acting on the glucose sensing and signaling pathway. In addition, we found that the wild-type level glucose uptake is essential for the full-level repression of inv1 expression.     

Comparative analysis of glycogen and trehalose accumulation in methylotrophic and nonmethylotrophic yeasts

Trehalose and glycogen accumulate in certain yeast species when they are exposed to unfavorable growth conditions. Accumulations of these reserve carbohydrates in yeasts provide resistance to stress conditions. The results of this study indicate that certain Pichia species do not accumulate high levels of glycogen and trehalose under normal growth conditions. However, depending on the Pichia species, both saccharides accumulate at high levels when the Pichia cells are exposed to unfavorable or stress-inducing growth conditions. Growth on glycerol or methanol mostly led to trehalose accumulation in Pichia species tested in this study. It was shown that the metabolic pathways for glycogen and trehalose biosynthesis are present in Pichia species. However, it appears that the biosynthesis of trehalose and glycogen may be regulated in different manners in Pichia species than in the yeast S. cerevisiae.     

The BTB-zinc Finger Transcription Factor Abrupt Acts as an Epithelial Oncogene in Drosophila melanogaster through Maintaining a Progenitor-like Cell State

The capacity of tumour cells to maintain continual overgrowth potential has been linked to the commandeering of normal self-renewal pathways. Using an epithelial cancer model in Drosophila melanogaster, we carried out an overexpression screen for oncogenes capable of cooperating with the loss of the epithelial apico-basal cell polarity regulator, scribbled (scrib), and identified the cell fate regulator, Abrupt, a BTB-zinc finger protein. Abrupt overexpression alone is insufficient to transform cells, but in cooperation with scrib loss of function, Abrupt promotes the formation of massive tumours in the eye/antennal disc. The steroid hormone receptor coactivator, Taiman (a homologue of SRC3/AIB1), is known to associate with Abrupt, and Taiman overexpression also drives tumour formation in cooperation with the loss of Scrib. Expression arrays and ChIP-Seq indicates that Abrupt overexpression represses a large number of genes, including steroid hormone-response genes and multiple cell fate regulators, thereby maintaining cells within an epithelial progenitor-like state. The progenitor-like state is characterised by the failure to express the conserved Eyes absent/Dachshund regulatory complex in the eye disc, and in the antennal disc by the failure to express cell fate regulators that define the temporal elaboration of the appendage along the proximo-distal axis downstream of Distalless. Loss of scrib promotes cooperation with Abrupt through impaired Hippo signalling, which is required and sufficient for cooperative overgrowth with Abrupt, and JNK (Jun kinase) signalling, which is required for tumour cell migration/invasion but not overgrowth. These results thus identify a novel cooperating oncogene, identify mammalian family members of which are also known oncogenes, and demonstrate that epithelial tumours in Drosophila can be characterised by the maintenance of a progenitor-like state.