Origin of rat β-globin haplotypes containing three and five genes

We have reported in rat three adult β-gene haplotypes containing either five or three genes. Detailed sequence analysis reveals that the leftmost gene is the major gene and that at the opposite end downstream lies the minor gene. All of the genes lying between them are minor-major hybrids indicating their origin by unequal crossing-over. In two haplotypes β-globin genes were found with an L1 element inserted directly into IVS2. The described results allow the formulation of a pathway of mutational events leading from the ancient two-β-gene rodent ancestor through a three-gene haplotype to five-gene haplotypes, one of which is postulated to have arisen in common laboratory strains since their capture in the wild.[https://academic.oup.com/mbe/article/7/5/407/1061225

Loss of Pluripotency in Human Embryonic Stem Cells Directly Correlates with an Increase in Nuclear Zinc

The pluripotency of human embryonic stem cells (hESCs) is important to investigations of early development and to cell replacement therapy, but the mechanism behind pluripotency is incompletely understood. Zinc has been shown to play a key role in differentiation of non-pluripotent cell types, but here its role in hESCs is directly examined. By mapping the distribution of metals in hESCs at high resolution by x-ray fluorescence microprobe (XFM) and by analyzing subcellular metal content, we have found evidence that loss of pluripotency is directly correlated with an increase in nuclear zinc. Zinc elevation not only redefines our understanding of the mechanisms that support pluripotency, but also may act as a biomarker and an intervention point for stem cell differentiation

Carbon nanotubes allow capture of krypton, barium and lead for multichannel biological X-ray fluorescence imaging

The desire to study biology in situ has been aided by many imaging techniques. Among these, X-ray fluorescence (XRF) mapping permits observation of elemental distributions in a multichannel manner. However, XRF imaging is underused, in part, because of the difficulty in interpreting maps without an underlying cellular ‘blueprint’; this could be supplied using contrast agents. Carbon nanotubes (CNTs) can be filled with a wide range of inorganic materials, and thus can be used as ‘contrast agents’ if biologically absent elements are encapsulated. Here we show that sealed single-walled CNTs filled with lead, barium and even krypton can be produced, and externally decorated with peptides to provide affinity for sub-cellular targets. The agents are able to highlight specific organelles in multiplexed XRF mapping, and are, in principle, a general and versatile tool for this, and other modes of biological imaging

Variant chromosomal arrangement of adult β-globin genes in rat

The genomic organization of three haplotypes of β-globin genes was determined to resolve the question of the number of those genes in rat. Haplotype a, found in inbred strain DA, has three genes or pseudogenes, while haplotypes b, found in AO, Y5 and Wistar strains, and c, found in Wistar strain, have five genes or pseudogenes each. In haplotypes b and c, the first gene is of βmajor type and the remaining four are of βminir type. Partial sequencing of six out of 13 genes shows that duplications of βminor genes are causing polymorphism in a number of genes. Also, in haplotype b two βminor genes have a 6.5-kb intron 2, while in haplotype c only one βminor gene contains such a large intron 2. The three structurally different haplotypes described are not interconvertible by single recombination events. The results indicate that the rat has the highest number of adult β-globin genes found in mammals so far

Changes in gene expression associated with radiation exposure

Current research from our group has demonstrated differences in gene induction patterns for high- and low-linear energy transfer radiations; some genes are induced selectively following neutron exposure, others selectively following {gamma}-ray exposure, and others induced following exposure to either. These genes are associated with a broad array of different functions including apoptosis, cytoskeletal function, and gene regulation (dd-RT-PCR) technology to identify genes induced following exposure to different qualities of radiation and following exposure to radiation in the presence of radioprotectors