Esrom, an ortholog of PAM (protein associated with c-myc), regulates pteridine synthesis in the zebrafish

Zebrafish esrom mutants have an unusual combination of phenotypes: in addition to a defect in the projection of retinal axons, they have reduced yellow pigmentation. Here, we investigate the pigment phenotype and, from this, provide evidence for an unexpected defect in retinal neurons. Esrom is not required for the differentiation of neural crest precursors into pigment cells, nor is it essential for cell migration, pigment granule biogenesis, or translocation. Instead, loss of yellow color is caused by a deficiency of sepiapterin, a yellow pteridine. The level of several other pteridines is also affected in mutants. Importantly, the cofactor tetrahydrobiopterin (BH4) is drastically reduced in esrom mutants. Mutant retinal neurons also appear deficient in this pteridine. BH4-synthesizing enzymes are active in mutants, indicating a defect in the regulation rather than production of enzymes. Esrom has recently been identified as an ortholog of PAM (protein associated with c-myc), a very large protein involved in synaptogenesis in Drosophila and C. elegans. These data thus introduce a new regulator of pteridine synthesis in a vertebrate and establish a function for the Esrom protein family outside synaptogenesis. They also raise the possibility that neuronal defects are due in part to an abnormality in pteridine synthesis.     

Thy-1, via its GPI anchor, modulates Src family kinase and focal adhesion kinase phosphorylation and subcellular localization, and fibroblast migration, in response to thrombospondin-1/hep I

Normal fibroblast subpopulations have differential surface expression of the GPI-linked raft protein Thy-1, which correlates with differences in cellular adhesion and migration in vitro. Thrombospondin-1 (TSP-1) induces an intermediate state of adhesion in fibroblasts and other cells which facilitates migration. TSP-1 and the hep I peptide derived from the amino-terminal/heparin-binding domain of TSP-1 induce disassembly of cellular focal adhesions. Our lab previously reported that the induction of focal adhesion disassembly in fibroblasts by TSP-1 or by hep I requires surface expression of Thy-1, as well as lipid raft integrity and Src family kinase (SFK) signaling. We now report that TSP-1/hep I-induced fibroblast migration requires Thy-1 expression and FAK phosphorylation, and that following TSP-1/hep I stimulation, Thy-1 associates with FAK and SFK in a lipid raft-dependent manner. Furthermore, the GPI anchor of Thy-1, which localizes the protein to specific lipid raft microdomains, is necessary for hep I-induced FAK and SFK phosphorylation, focal adhesion disassembly, and migration. This is the first report of an association between Thy-1 and FAK. Thy-1 modulates SFK and FAK phosphorylation and subcellular localization, promoting focal adhesion disassembly and migration in fibroblasts, following exposure to TSP-1/hep I.     

Detection of minisatellite sequences inPhaseolus vulgaris

An improved procedure for detecting minisatellite sequences inPhaseolus vulgaris is described. Both M13 protein III tandem repeat and the 33.15 human mini-satellite sequences revealed polymorphisms with a high number of sharp bands after digestion of genomic DNA withHae III,Hinf I, orTaq I. Improved resolution of the numerous restriction fragments detected by these probes is accomplished by one or more of the following: varying agarose concentration, using high SDS hybridization buffer, exposure of the autoradiograph without intensifying screens, and transfer of the autoradiograph to electrophoresis paper. Increased stability of the DNA-DNA hybridizations with these heterologous probes is obtained by reducing hybridization temperature. Labeling probes with the polymerase chain reaction can accentuate some restriction fragments depending upon the radiolabeled nucleotide used.     

载脂蛋白E基因多态性在中国4个民族中的分布

本研究提取中国东北汉族和达斡尔、鄂伦春、鄂温克等４个人群的基因组ＤＮＡ后,利用ＰＣＦ－ＲＦＬＰ方法扩增ａｐｏ Ｅ基因等４外显子片段并进行遗传分析,计算各个人群中的ａｐｏ Ｅ等位基因频率。结果发现４个人群中的ａｐｏ Ｅ等位基因频率分布趋势与国风个报告基本一致,但等位基因ε３的频率显著高于欧美国家。