Interstrand crosslink-induced radials form between non-homologous chromosomes, but are absent in sex chromosomes

Fanconi anemia (FA) and cells lacking functional BRCA1 and BRCA2 proteins are hypersensitive to interstrand crosslinking (ICL) agents and show increased numbers of chromosomal breaks and radials. Although radial formation has been used to diagnose FA for more than 30 years, there has been little analysis of these characteristic formations. In this study, radials were analyzed from FA-A and FA-G fibroblasts as well as normal and retrovirally-corrected FA-A fibroblasts treated with high doses of ICLs. Radials were found to only involve non-homologous chromosome interactions and to be distributed nearly randomly along the length of chromosomes. Sites on chromosomes that did show increased frequency of radial involvement did not correlate with known fragile sites or pericentric regions. Hybrid radials were observed between mouse and human chromosomes in human-mouse hybrid cells produced by microcell-mediated chromosome transfer of mouse chromosomes into human FA-A fibroblasts. Both X and Y chromosomes were notably not involved in radials. These observations suggest that ICL repair may involve short stretches of homology, resulting in aberrant radial formation in the absence of FA proteins.     

Fanconi Anemia: A Decade of Discoveries

In 1967, Guido Fanconi, a Swiss pediatrician, described Fanconi anemia (FA) in two siblings with similar physical anom-alies and bone marrow failure.1 A few years earlier, Schroeder and colleagues had described an increase in spontaneous chromosome breaks in blood samples from patients afflicted with what was then called familial panmyelopathy,2 now known to have been FA. Since then, the field of FA research has undergone an amazing revolution, especially in the last decade. Because of its relation-ship to DNA repair and association with a susceptibility to neo-plastic transformation, FA has gained much attention, particularly following the elucidation of some of the genes that are mutated in FA patients. In 2002, the discovery of a connection between FA, breast cancer, and other well-known DNA repair diseases sparked numerous publications on the subject. In this review, we discuss the clinical and genetic aspects of FA.     

Expression and biological activity of Baculovirus generated wild-type human slow alpha tropomyosin and the Met9Arg mutant responsible for a dominant form of nemaline myopathy

We have previously reported a Met9Arg mutation in the human skeletal muscle alpha tropomyosin gene (TPM3) associated with autosomal dominant nemaline myopathy [Nat. Genet. 9 (1995) 75]. We describe here the generation of wild-type (Wt-tpm3) and Met9Arg (M9R-tpm3) mutant human skeletal muscle slow alpha tropomyosin using the Baculovirus expression vector system (BEVS). This system produces correct posttranslationally modified recombinant tropomyosin proteins in insect cells. We show that the interactions of Wt-tpm3 with actin and tropomyosin are comparable to those of fast alpha tropomyosin isolated from chicken striated muscle. However, the recombinant M9R-tpm3 is at least 100 times less effective at binding actin than Wt-tpm3. This paper represents the first study of this mutation directly on the human isoform of tropomyosin that is involved in nemaline myopathy. It also represents the first time that human tpm3 has been produced using BEVS. This system can now be used to accurately demonstrate the effect of this (and other disease-associated tropomyosin mutations) on the interactions of tpm3 with the other protein components of the muscle thin filament, including those responsible for differing forms of nemaline myopathy.     

Gamma-tubulin at ten: progress and prospects

The existence of gamma-tubulin was first reported approximately ten years ago, and it is appropriate to review the progress that has been made in gamma-tubulin research and to discuss some of the unanswered questions about gamma-tubulin function. gamma-Tubulin is ubiquitous in eukaryotes and is generally quite conserved. Two highly divergent gamma-tubulins have been discovered, however, one in Saccharomyces cerevisiae and one in Caenorhabditis elegans. Several organisms have two gamma-tubulin genes. In Drosophila melanogaster, the two gamma-tubulins differ significantly in sequence and expression pattern. In other organisms the two gamma-tubulins are almost identical and expression patterns have not been determined. gamma-Tubulin is located at microtubule organizing centers in many organisms, and it is also frequently associated with the mitotic spindle. gamma-Tubulin is essential for the formation of functional mitotic spindles in all organisms that have been examined to date. In animal cells, complexes containing gamma-tubulin are located at microtubule organizing centers where they nucleate the assembly of microtubules. In spite of the considerable progress that has been made in gamma-tubulin research important questions remain to be answered. The exact mechanisms of microtubule nucleation by gamma-tubulin complexes remain to be resolved as do the mechanisms by which microtubule nucleation from gamma-tubulin complexes is regulated. Finally, there is evidence that gamma-tubulin has important functions in addition to microtubule nucleation, and these functions are just beginning to be investigated.     

Virion-Targeted Viral Inactivation of Human Immunodeficiency Virus Type 1 by Using Vpr Fusion Proteins

Inactivation of progeny virions with chimeric virion-associated proteins represents a novel therapeutic approach against human immunodeficiency virus (HIV) replication. The HIV type 1 (HIV-1) Vpr gene product, which is packaged into virions, is an attractive candidate for such a strategy. In this study, we developed Vpr-based fusion proteins that could be specifically targeted into mature HIV-1 virions to affect their structural organization and/or functional integrity. Two Vpr fusion proteins were constructed by fusing to the first 88 amino acids of HIV-1 Vpr the chloramphenicol acetyltransferase enzyme (VprCAT) or the last 18 C-terminal amino acids of the HIV-1 Vpu protein (VprIE). These Vpr fusion proteins were initially designed to quantify their efficiency of incorporation into HIV-1 virions when produced in cis from the provirus. Subsequently, CD4⁺ Jurkat T-cell lines constitutively expressing the VprCAT or the VprIE fusion protein were generated with retroviral vectors. Expression of the VprCAT or the VprIE fusion protein in CD4⁺ Jurkat T cells did not interfere with cellular viability or growth but conferred substantial resistance to HIV replication. The resistance to HIV replication was more pronounced in Jurkat-VprIE cells than in Jurkat-VprCAT cells. Moreover, the antiviral effect mediated by VprIE was dependent on an intact p6^gag domain, indicating that the impairment of HIV-1 replication required the specific incorporation of Vpr fusion protein into virions. Gene expression, assembly, or release was not affected upon expression of these Vpr fusion proteins. Indeed, the VprIE and VprCAT fusion proteins were shown to affect the infectivity of progeny virus, since HIV virions containing the VprCAT or the VprIE fusion proteins were, respectively, 2 to 3 times and 10 to 30 times less infectious than the wild-type virus. Overall, this study demonstrated the successful transfer of resistance to HIV replication in tissue cultures by use of Vpr-based antiviral genes.     

New horizons in culture and valorization of red microalgae

Research on marine microalgae has been abundantly published and patented these last years leading to the production and/or the characterization of some biomolecules such as pigments, proteins, enzymes, biofuels, polyunsaturated fatty acids, enzymes and hydrocolloids. This literature focusing on metabolic pathways, structural characterization of biomolecules, taxonomy, optimization of culture conditions, biorefinery and downstream process is often optimistic considering the valorization of these biocompounds. However, the accumulation of knowledge associated with the development of processes and technologies for biomass production and its treatment has sometimes led to success in the commercial arena. In the history of the microalgae market, red marine microalgae are well positioned particularly for applications in the field of high value pigment and hydrocolloid productions. This review aims to establish the state of the art of the diversity of red marine microalgae, the advances in characterization of their metabolites and the developments of bioprocesses to produce this biomass.     

Does post-warm-up rest interval affect the diurnal variation of 30-s Wingate cycle ergometry?

The purpose of this investigation was to assess the effects of rest interval following active warm-up (WU) durations on the diurnal variation of high-intensity cycling performance. Eleven male physical education students (22.6 ± 2.5 years; 179.2 ± 5.7 cm; 82.6 ± 9.6 kg; mean ± SD) participated in a cross-over randomized study, and they all underwent the 30-s Wingate test in the morning (08:00 h) and in the evening (18:00 h), after 5-min (WU₅) and 15-min (WU₁₅) warm-up durations, either with rest (WR), or without rest interval (NR) separating the WU at the onset of the high-intensity cycling exercise performance. The WU consisted of pedaling at a constant pace of 60 rpm against at 50% of the maximal aerobic power. The rest interval between the end of warm-up and the beginning of the anaerobic exercise was set at 5 min. Peak power (PP), mean power (MP), and the fatigue index (FI) were recorded. Likewise, heart rate, oral temperature (T), and rating of perceived exertion were registered at rest, at the end of the WU and just after the Wingate test. The ANOVA’s showed no main effect of the rest interval on PP, MP, FI, and T parameters. However, significant interactions (WU duration × time-of-day and recovery condition × WU duration) were recorded on both PP and MP parameters. PP and MP were higher in the afternoon compared to the morning with gains of 4.4 and 3.6%, respectively. In the morning sessions, the WU₁₅ allows better improvement of muscular power, with either 0- or 5-min pre-exercise rest interval. However, in the afternoon sessions, both WU₁₅ and WU₅ durations allow better improvement of 30-s Wingate cycling performance in, respectively, WR and NR conditions. Therefore, athletes and coaches, as well as researchers, interested in high-intensity cycling exercise, should take into account the rest interval, the time-of-day, and the duration of warm-up when practicing, assessing, or interpreting data related to powerful lower limbs’ muscles contractions activities.     

A New Dimension in Documenting New Species: High-Detail Imaging for Myriapod Taxonomy and First 3D Cybertype of a New Millipede Species (Diplopoda,Julida, Julidae)

We review the state-of-the-art approaches currently applied in myriapod taxonomy, and we describe, for the first time, a new species of millipede (Ommatoiulus avatar n. sp., family Julidae) using high-resolution X-ray microtomography (microCT) as a substantive adjunct to traditional morphological examination. We present 3D models of the holotype and paratype specimens and discuss the potential of this non-destructive technique in documenting new species of millipedes and other organisms. The microCT data have been uploaded to an open repository (Dryad) to serve as the first actual millipede cybertypes to be published.