Genomic Analysis of a New Mammalian Distal-less Gene: Dlx7

We have cloned a new Dlx gene (Dlx7) from human and mouse that may represent the mammalian orthologue of the newt geneNvHBox-5.The homeodomains of these genes are highly similar to all other vertebrate Dlx genes, and regions of similarity also exist between mammalian Dlx7 and a subset of vertebrate Dlx genes downstream of the homeodomain. The sequence divergence between human and mouse Dlx7 in these regions is greater than that predicted from comparisons of other vertebrate Dlx genes, however, and there is little sequence similarity upstream of the homeodomain both between these two genes and with other Dlx genes. We present evidence for alternative splicing of mouseDlx7upstream of the homeodomain that may account for some of this divergence. We have mapped humanDLX7distal to the 5′ end of the HOXB cluster at an estimated distance of between 1 and 2 Mb by FISH. Both the human and the mouse Dlx7 are shown to be closely linked to Dlx3 in a convergently transcribed orientation. These mapping results support the possibility that vertebrate distal-less genes have been duplicated in concert with the Hox clusters.     

Identification of molecular markers in soybean comparing RFLP,RAPD and AFLP DNA mapping techniques

Three different DNA mapping techniques—RFLP, RAPD and AFLP—were used on identical soybean germplasm to compare their ability to identify markers in the development of a genetic linkage map. Polymorphisms present in fourteen different soybean cultivars were demonstrated using all three techniques. AFLP, a novel PCR-based technique, was able to identify multiple polymorphic bands in a denaturing gel using 60 of 64 primer pairs tested. AFLP relies on primers designed in part on sequences for endonuclease restriction sites and on three selective nucleotides. The 60 diagnostic primer pairs tested for AFLP analysis each distinguished on average six polymorphic bands. Using specific primers designed for soybean fromEco RI andMse I restriction site sequences and three selective nucleotides, as many as 12 polymorphic bands per primer could be obtained with AFLP techniques. Only 35% of the RAPD reactions identified a polymorphic band using the same soybean cultivars, and in those positive reactions, typically only one or two polymorphic bands per gel were found. Identification of polymorphic bands using RFLP techniques was the most cumbersome, because Southern blotting and probe hybridization were required. Over 50% of the soybean RFLP probes examined failed to distinguish even a single polymorphic band, and the RFLP probes that did distinguish polymorphic bands seldom identified more than one polymorphic band. We conclude that, among the three techniques tested, AFLP is the most useful.     

An Integrated Map with Cosmid/PAC Contigs of a 4-Mb Down Syndrome Critical Region

The major phenotypic features of Down syndrome have been correlated with partial trisomies of chromosome 21, allowing us to define the candidate gene region to a 4-Mb segment on the 21q22.2 band. We present here a high-resolution physical map with megabase-sized cosmid/PAC contigs. This ordered clone library has provided unique material for the integration of a variety of mappable objects, including exons, cDNAs, restriction sites, etc. Furthermore, our results have exemplified a strategy for the completion of the chromosome 21 map to sequencing.     

固定化虫荧光素酶光纤传感器

固定化虫荧光素酶光纤传感器蔡谨,王顺光,杨歧生,吉鑫松（浙江大学化工系生化教研室,杭州３１００２７;中国科学院上海生物化学研究所,２０００３１）关键词虫荧光素酶,ＡＴＰ,固定化酶,光纤生物传感器ＡＴＰ是生物体内极为重要的能量物质。如何准确快速地定量Ａ...     

人分裂细胞核抗原基因片段的筛选、测序及对启动子的分析

经６．６×１０５个克隆筛选,从装在λ噬菌体载体Ｃｈａｒｏｎ３０中的人基因库中筛选到了一个含人分裂细胞核抗原（ＰＣＮＡ）基因的克隆。经Ｓｏｕｔｈｅｒｎ杂交分析插入基因长约１４ｋｂ,有较长的５＇上游区,但３＇端缺少一部分。经亚克隆和测序已确定从５＇上游１２６３ｂｐ到３＇端与λ载体接点共４９６９ｂｐＰＣＮＡ基因片段的核苷酸序列。将ＰＣＮＡ基因启动子核苷酸序列与ＤＮＡ聚合酶α,拓扑异构酶Ⅱα,胸苷酸激酶基因的启动子进行比较有３０％以上同源性,具有“看家基因”特征。在转录起始点的５＇上游几百ｂｐ的范围内都有与ＣＡＴ,ＳＰ１,Ｅ２Ｆ,ＮＦＨＢ,Ｏｃｔ１和ＡＴＦ等转录因子的结合位点相似的核苷酸序列。     

细胞骨架对凝血酶诱导人血小板分泌反应的调节(英文)

本文利用血小板表面外露的GMP-140为血小板分泌反应的特异性标志,通过放射免疫分析法定量测定血小板表面GMP-140分子数,研究了细胞骨架抑制剂对凝血酶诱导血小板分泌反应的影响。结果表明,凝血酶激活使血小板表面GMP-140的外露明显增加,反应迅速,并在一定范围内呈剂量和时间依赖性;而ADP刺激则几乎不引起GMP-140外露的增加。凝血酶激活前加入不同的细胞骨架抑制剂处理可产生不同的效应:细胞松驰素B(肌动蛋白微丝抑制剂)可明显上调凝血酶诱导的GMP-140外露;而秋水仙素(微管抑制剂)则下调GMP-140的外露;两者同时处理仍呈现明显的上调作用。提示凝血酶作为一种强激活剂,不仅可通过受体-G蛋白-第二信使的途径启动血小板分泌反应,而且可能经诱导肌动蛋白微丝的形成对分泌反应起反馈性负调节作用。微管的存在则可能对凝血酶诱导的分泌反应起促进作用。虽然两种细胞骨架的作用相反,但以微丝的作用为主,两者间无相互拮抗现象。     

拟夏孢锈属（Uredinopsis）新记录种

采到骨状拟夏孢锈（Ｕｒｅｄｉｎｏｐｓｉｓ ｏｓｓｉｆｏｒｍｉｓ Ｋａｍｅｉ）为中国新记录种。     

大豆籽粒蓝脐性状及其分离规律

控制大豆白花亲本籽粒脐色的基因有带Ｒ与ｒ之分,带Ｒ基因的白花产本与紫花亲本杂交,Ｆ１代籽料出现蓝脐性状,其基因型为Ｉ－Ｒ－Ｗ１－ｔｔ。当控制脐色的基因有两对相差时（Ｒ、ｒ;Ｗ１、ｗ１）Ｆ２代籽粒脐色分离蓝脐与无色脐之比为９∶７。     

钙调素对细胞周期的调节

RC3细胞是一种用真核表达载体1~(CaM)转染NIH 3T3细胞建成的可调钙凋素(Calmodulin,CaM)高表达细胞模型。通过分子杂交及蛋白免疫印迹方法证实在地塞米松(Dexamethasome,DXM)作用下,RC3细胞可高表达CaM。CaM的过表达使G_1期细胞减少,S期细胞增加;CaM拮抗剂三氟拉嗪(trifluoperazine,TFP)则使G_1期细胞增加,S期细胞减少。高表达CaM使细胞分裂指数提高,G_2期细胞减少,有丝分裂前期细胞增加,M中期细胞比例下降。而TFP处理则使分裂指数下降,G_2期细胞增加,M前期细胞减少,M中期细胞增加。实验结果表明CaM在G_1/S、G_2/M和M中期/M后期3个位点上对细胞周期进行调控;通过加速G_1至S期,G_2至M期和M中期至M后期的进程,使细胞倍增时间缩短,促进细胞增殖。本工作表明,RC3细胞作为CaM表达可调细胞模型,是研究细胞周期调控的有力工具。