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Several Phenotypic Traits (several + phenotypic_trait)

Distribution by Scientific Domains

Life Sciences	80%

Selected Abstracts

A GyrB-GyrA fusion protein expressed in yeast cells is able to remove DNA supercoils but cannot substitute eukaryotic topoisomerase II

GENES TO CELLS, Issue 3 2002
Sonia Trigueros
Background: Type II topoisomerases are a highly conserved class of enzymes which transport one double-stranded DNA segment through a transient break in another. Whereas the eukaryotic enzymes are homodimers of a single polypeptide, their bacterial homologues are homodimers of two independently coded protein subunits. Unlike eukaryotic topoisomerase II and bacterial topoisomerase IV, DNA gyrase is a bacterial type II topoisomerase which specializes in intramolecular DNA transport. Results: We have fused the Escherichia coli coding sequences for the proteins GyrB and GyrA, which comprise DNA gyrase. This fusion was expressed in yeast cells and yielded the expected full-length protein product. When it was expressed in ,top1- top2-4 yeast cells, the fusion protein compensated their slow growth and reverted their elevated chromosomal excision of ribosomal genes. Furthermore, it removed DNA positive supercoils. The fusion protein, however, was unable to complement the temperature-dependent lethality of top2-4 cells. Conclusion: Fusion of the E. coli GyrB and GyrA proteins leads to a catalytically active topoisomerase which compensates several phenotypic traits attributed to unconstrained DNA supercoiling in topoisomerase-deficient cells. However, since the fusion protein cannot substitute for topoisomerase II, it may be efficient in intramolecular but not intermolecular DNA passage, resembling the catalytic properties of DNA gyrase. [source]

The Aspergillus nidulans sldIRAD50 gene interacts with bimEAPC1, a homologue of an anaphase-promoting complex subunit

MOLECULAR MICROBIOLOGY, Issue 1 2005
Iran Malavazi
Summary The Mre11,Rad50,Nbs1 protein complex has emerged as a central component in the human cellular DNA damage response, and recent observations suggest that these proteins are at least partially responsible for the linking of DNA damage detection to DNA repair and cell cycle checkpoint functions. We have identified Aspergillus nidulans sldI1444D mutant in a screen for dynein synthetic lethals. The sldIRAD50 gene was cloned by complementation of the sporulation deficiency phenotype of this mutant. A transversion G,C at the position 2509 (Ala-692-Pro amino acid change) in the sldI1444D mutant causes sensitivity to several DNA-damaging agents. The mutation sldI1 occurs at the CXXC hinge domain of Rad50. We have deleted part of the coiled-coil and few amino acids of the Rad50,Mre11 interaction region and assessed several phenotypic traits in this deletion strain. Besides sensitivity to a number of DNA-damaging agents, this deletion strain is also impaired in the DNA replication checkpoint response, and in ascospore viability. There is no delay of the S-phase when germlings of both sldI RAD50 and mreAMRE11 inactivation strains were exposed to the DNA damage caused by bleomycin. Transformation experiments and Southern blot analysis indicate homologous recombination is dependent on scaANBS1 function in the Mre11 complex. There are epistatic and synergistic interactions between sldI RAD50 and bimEAPC1 at S-phase checkpoints and response to hydroxyurea and UV light. Our results suggest a possible novel feature of the Mre11 complex in A. nidulans, i.e. a relationship with bimE,APC1. [source]

Analyses of GA20ox - and GID1 -over-expressing aspen suggest that gibberellins play two distinct roles in wood formation

THE PLANT JOURNAL, Issue 6 2009
Mélanie Mauriat
Summary Gibberellins (GAs) are involved in many aspects of plant development, including shoot growth, flowering and wood formation. Increased levels of bioactive GAs are known to induce xylogenesis and xylem fiber elongation in aspen. However, there is currently little information on the response pathway(s) that mediate GA effects on wood formation. Here we characterize an important element of the GA pathway in hybrid aspen: the GA receptor, GID1. Four orthologs of GID1 were identified in Populus tremula × P. tremuloides (PttGID1.1,1.4). These were functional when expressed in Arabidopsis thaliana, and appear to present a degree of sub-functionalization in hybrid aspen. PttGID1.1 and PttGID1.3 were over-expressed in independent lines of hybrid aspen using either the 35S promoter or a xylem-specific promoter (LMX5). The 35S:PttGID1 over-expressors shared several phenotypic traits previously described in 35S:AtGA20ox1 over-expressors, including rapid growth, increased elongation, and increased xylogenesis. However, their xylem fibers were not elongated, unlike those of 35S:AtGA20ox1 plants. Similar differences in the xylem fiber phenotype were observed when PttGID1.1, PttGID1.3 or AtGA20ox1 were expressed under the control of the LMX5 promoter, suggesting either that PttGID1.1 and PttGID1.3 play no role in fiber elongation or that GA homeostasis is strongly controlled when GA signaling is altered. Our data suggest that GAs are required in two distinct wood-formation processes that have tissue-specific signaling pathways: xylogenesis, as mediated by GA signaling in the cambium, and fiber elongation in the developing xylem. [source]

Analysis of ancient human genomes

BIOESSAYS, Issue 5 2010
000-year-old human from Greenland has been obtained, 20-fold coverage of the genome of a , Using next generation sequencing
Abstract High-capacity sequencing technologies have dramatically reduced both the cost and time required to generate complete human genome sequences. Besides expanding our knowledge about existing diversity, the nature of these technologies makes it possible to extend knowledge in yet another dimension: time. Recently, the complete genome sequence of a 4,000-year-old human from the Saqqaq culture of Greenland was determined to 20-fold coverage. These data make it possible to investigate the population affinities of this enigmatic culture and, by identifying several phenotypic traits of this individual, provide a limited glimpse into how these people may have looked. While undoubtedly a milestone in ancient DNA research, the cost to generate an ancient genome, even from such an exceptionally preserved specimen, remains out of reach for most. Nonetheless, recently developed DNA capture methods, already applied to Neanderthal and fossil human mitochondrial DNA, may soon make large-scale genome-wide analysis of ancient human diversity a reality, providing a fresh look at human population history. [source]

Influence of parental origin of the X chromosome on physical phenotypes and GH responsiveness of patients with Turner syndrome

CLINICAL ENDOCRINOLOGY, Issue 1 2010
Jung Min Ko
Summary Objective, Previous studies have reported the effects of parental origin of the X chromosome on specific phenotypic and cognitive profiles in Turner syndrome (TS). Here, we investigate the possible parent-of-origin effects on physical phenotypes and responsiveness to GH in Korean patients with TS. Design and patients, Thirty-three patients with TS with nonmosaic karyotype and their parents participated in this study. The parental origin of the normal X chromosome was determined by comparing parental DNA polymorphisms using nine highly polymorphic microsatellite markers on the X chromosome. For the evaluation of parent-of-origin effects, typical phenotypic traits, including congenital malformations, auxological and endocrinological profiles, were compared. Results, The retained X chromosome was of maternal (Xm) origin in 60·6% patients and paternal (Xp) origin in 39·4% patients. No significant parent-of-origin effects on stature, body mass index, cardiac, renal, skeletal, lymphatic, hearing or ocular systems were evident. We observed no differences in height gain after GH treatment. In patients with the 45,X karyotype, patient height was positively correlated with maternal height in the Xm group (r = 0·60, P = 0·04). Moreover, patient height was more significantly correlated with maternal than paternal height, irrespective of the parental origin of the retained X chromosome. Conclusion, While we observed no significant impact of parental origin of the X chromosome on several phenotypic traits in patients with TS, a maternal imprinting effect on stature was suggested at least in patients with 45,X. Further studies on a larger number of patients with TS are essential to define the potential imprinting effects of undetermined genes on the X chromosome. [source]