Project description:To identify novel mechanisms regulating allogeneic hematopoietic cell engraftment, we previously used a forward genetic approach and described identification, in mice, of the Bmgr5 bone marrow (BM) engraftment quantitative trait locus (QTL). This QTL confers dominant and large allele effects for engraftment susceptibility. It was localized to chromosome 16 by classical quantitative genetic techniques in a segregating backcross bred from susceptible BALB.K and resistant B10.BR mice. We now report verification of the Bmgr5 QTL using reciprocal chromosome 16 consomic strains. The BM engraftment phenotype in these consomic mice shows that Bmgr5 susceptibility alleles are not only sufficient but also indispensable for conferring permissiveness for allogeneic BM engraftment. Using panels of congenic mice, we resolved the Bmgr5 QTL into two separate subloci, termed Bmgr5a and Bmgr5b, each conferring permissiveness for the engraftment phenotype and both fine mapped to an interval amenable to positional cloning. Candidate Bmgr5 genes were then prioritized using whole exome DNA sequencing and microarray gene expression profiling. Further studies are needed to elucidate the genetic interaction between Bmgr5a and Bmgr5b and identify causative genes and underlying gene variants. This may lead to new approaches for overcoming the problem of graft rejection in clinical hematopoietic cell transplantation.
Project description:In the family Fagaceae, fertilization is delayed by several weeks to more than one year after pollination, leading to one- or two-year fruiting species depending on whether fruiting occurs in the same or the next year of flowering. Although delayed fertilization was recorded over a century ago, underlying mechanisms remain to be explored. To uncover the key genes associated with delayed fertilization, we obtain and analyze the comparative molecular phenology data over two years in one-year (Quercus glauca) and two-year fruiting species (Lithocarpus edulis).
Project description:In the family Fagaceae, fertilization is delayed by several weeks to more than one year after pollination, leading to one- or two-year fruiting species depending on whether fruiting occurs in the same or the next year of flowering. Although delayed fertilization was recorded over a century ago, underlying mechanisms remain to be explored. To uncover the key genes associated with delayed fertilization, we obtain and analyze the comparative molecular phenology data over two years in one-year (Quercus glauca) and two-year fruiting species (Lithocarpus edulis).
Project description:Myxococcus xanthus is a model organism for studying social behaviors and cell differentiation in bacteria. Upon nutrient depletion, M. xanthus cells initiate a developmental program that culminates in formation of spore-filled fruiting bodies and peripheral rods outside of fruiting bodies. Completion of this developmental program depends on fine-tuned spatial and temporal regulation of gene expression, intercellular communication, signaling by nucleotide-based second messengers, and motility. In order to understand stage-specific gene expression during growth and development, we extracted total RNA from vegetative cells (referred as 0 h of development) and from cells developed for 6, 12, 18 and 24 h under submerged conditions in two replicates.
Project description:Abstract:Genetical genomics has been suggested and proven to be a powerful approach to study the genotype-phenotype gap. However, the relatively low power of these experiments (usually related to the high cost) has hindered fulfilment of its promise, especially for loci (QTL) of moderate effects. One strategy to overcome the issue is to use a targeted approach: to focus the experiment on one QTL of particular interest. It has two clear advantages: (i) It reduces the problem to a simple comparison between different genotypic groups at the QTL and (ii) it is a good starting point to investigate downstream effects of the QTL. In the present study, from 698 F2 birds used for QTL mapping, gene expression profiles of 24 (12 from each homozygote genotypes at the QTL) were investigated. The targeted QTL was located on chromosome 1 and affected initial pH of meat. The biological mechanisms controlling this trait can be similar to those affecting malignant hyperthermia or muscle fatigue in human. The gene expression study identified ten strong local signals (potentially cis-eQTL) which were markedly more significant compared to the rest of the genome. The differentially expressed genes all mapped to a region < 1 Mb, suggesting a remarkable reduction of the QTL interval compared to the linkage study. These results combined with analysis of downstream effect of the QTL (using gene network analysis) suggest that the QTL is controlling pH by governing oxidative stress. The eQTL results were reproducible with using as few as 4 arrays on pooled samples (with lower significance level). The results demonstrate that this cost effective approach is promising not only for characterization of a QTL also for studying its downstream effects.