逆向遗传分析与遗传工程小鼠

遗传学的实验研究往往是从生物体的突变分析入手,通过观察自发的或诱发的突变型个体表型改变来识别突变基因,进而识别与突变基因等位的正常基因的结构与功能.但是,随着研究的深入,这种传统思路的局限性慢慢显现出来.譬如,许多能造成致死表型的突变,很可能因阻断重要的发育或代谢途径而导致携有突变基因的个体死亡.而分离和研究这类突变基因对于阐明生长、发育、疾病、衰老乃至进化等基本生物学问题至关重要.     

Fine mapping of the dominant glandless Gene Gl2^e in Sea-island cotton （Gossypium barbadense L.）

Gle2 is a mutant gene that controls glandless trait in cotton plants and seeds. It is an important gene resource to gossypol-free cottonseed breeding. The objective of this research was to develop SSR markers tightly linked with Gle2 by using the F2 segregating population containing 1599 plants derived from the cross of G. hirsutum genetic standard line TM-1 and G. barbadense glandless mutant line Hai-1. Genetic analysis suggested that the Gle2 was an incomplete dominant gene. Based on the backbone of genetic linkage map from G. hirsutum × G. barbadense BC1 published by our laboratory,Gle2 was lo-cated between CIR362 and NAU2251b,NAU3860b,STV033,with a genetic distance 9.27 and 0.96 cM,respectively. This result is useful for cloning Gle2 gene by map-based cloning method.     

苯丙氨酸羟化酶基因内点突变的检测与分析

目的 为了检测江苏省地区苯丙酮尿症患血苯丙氨酸羟桦酶基因内突为点及其对ＰＫＵ致病的相关性，从分子水平上提高诊断率。方法：采用了４对引物，外显子４、７、１１、（Ｅ４、Ｅ７、Ｅ１１）及ＳＴＲ，应用多聚酶链反应单链构象多态（ＰＣＲ－ＳＳＣＰ）银染技术检测分析了６个ＰＫＵ家系共２１个成员。结果：２１例检测样品中１个家系４位成员测出Ｅ４基因突变，父母为不同的点突变的携带，子女为遗传复合体。     

一例中国人BMD家系突变基因的起源

Becker型肌营养不良症(Becker muscular dystrophy,BMD)是一种较常见的X-连锁隐性神经肌肉疾患,发病率占出生男性的3—6/10万。它与Duchenne型肌营养不良症(Duchenne muscular dystrophy,DMD)相比,发病较迟,病程进展较缓慢,患者存活时间长。BMD基因和DMD基因位于同一位点,互为等位关系。     

广西发现世界首例缺失型α地中海贫血突变基因

记者5日从广西壮族自治区人民医院获悉,经过近2年的研究,该院检验科主管技师李友琼等医务人员发现了世界首例缺失型α地中海贫血突变基因,并于日前在美国DNA数据库成功注册。这一新突变基因的发现,不仅丰富了世界地中海贫血突变基因数据库,同时为在临床上避免地贫患儿的降生及科学研究提供了新的参考信息。     

一个绿色荧光蛋白K79R突变gfp基因的鉴定与表达

在开展蓝色荧光蛋白基因bfp的克隆表达研究中,发现一个发强绿色荧光的大肠杆菌突变株,从中提取质粒命名为pHN122.经酶切鉴定、亚克隆和序列分析测定结果证实其上含有一个bfp和一个发生了K79R突变的gfp基因.光谱分析结果表明:GFPK79R的光谱特性虽与野生型gfp相同,但其发光强度提高了1.25～2.44倍.     

小鼠也科技

老鼠虽然长相不好看，也不怎么招人爱，但它却为人类的科研做出了积极的贡献。正因为如此，它们可是科研单位的“宝贝”。目前南京大学已成为国内最大的遗传工程小鼠资源中心，资源库现有小鼠品系264种，在养小鼠达到3万余只。     

无毛突变基因对无毛小鼠免疫器官结构及功能的影响

摘要: 目的探讨无毛突变基因的作用,对无毛小鼠、有毛小鼠的免疫器官结构及功能进行了对比研究。方法比 较无毛小鼠和有毛小鼠主要免疫器官组织学变化,以及血清白介素－ 2 受体、淋巴细胞亚群、淋巴细胞增殖等方面 的差别。结果发现无毛小鼠和有毛小鼠免疫器官结构及功能均有一定的差异。结论研究结果提示无毛突变 基因不仅影响被毛结构,对免疫器官及功能也有一定的影响。该基因在杂合状态时也有一定的作用,表明该突变 基因具有一定的共显性。     

定点突变提高豆豉纤溶酶的酶活力和底物特异性的研究

以pBE—DFE质粒为模板,采用反向长距离PCR技术对豆豉纤溶酶(Douchi Fibrinolytic Enzyme,DFE)基因进行定点突变,使位于酶的底物结合区第156位的谷氨酸和第166位的甘氨酸分别替换为丝氨酸和丙氨酸,使临近酶的底物结合区的第169位甘氨酸残基替换为丙氨酸,获得了三个突变体E156S,G166A和G169A.将含突变基因的表达载体转化枯草杆菌WB800,构建了豆豉纤溶酶基因突变体的表达菌株WB800(E156S);WB800(G166A)和WB800(G166A).将3种表达菌株进行液体发酵培养,结果发现发酵上清液中纤溶酶的纤溶活性为460,790和900U/mL,分别是未突变酶活性(660U/mL)的70%,115%和136%;3种突变酶对合成底物的H-D-Val-Leu-Lys-pNA的酰胺水解活性是未突变酶的17%,125%和121%.     

Construction and genetic analysis of mutator insertion mutant population in maize

A total of 26718 M1 plants were ob- tained by crossing the active mutator transposon donor parents (Q105, WW51, 115F, V26-2 and 919J) with the recipient parents (Hz85,W328 with Bz gene and S-Mo17Rf3Rf3). The phenotypes of M1 plants were observed in the field. M1 plants were self-pollinated to develop the mutator insertion-mutagenized M2 seeds. The transposition frequency of the mutator in the genome was calculated based on the spotted aleurone phenotype of the M2 seeds. The results showed that: (1) the mutation frequency of M1 phe- notypes in the field was 0.07 in the population of W328×Mu; (2) the mutation frequency of spotted aleurone seeds on the M2 ears was 0.122 in the population of W328×Mu; (3) five S-cytoplasm male-sterile plants were found among 22500 M1 plants of S-Mo17Rf3Rf3×Mu, with the transposition frequency about 2.2×10?4 per locus. 99 flanking se- quences of mutator transposition were amplified by the modified MuTAIL-PCR, and 59 non-redundant sequences with length around 400 bp were obtained. After bioinformatic analysis, 27 sequences of them could be annotated, using non-redundant nucleotide database of maize, rice, and Arabidopsis. 36 se- quences of them were located on the genetic map of maize by comparative genomics, and several flank- ing sequences of mutator insertion were mapped on the single marker locus. Hotspot sequences of mu- tator transposition were revealed by comparing the homologies between the 9-bp target site duplication of the mutator insertion. The putative functions of 8 flanking sequences of mutator transposition had identity with the functions of their correspondingmarker. The constructed mutator insertion mutant population in maize will facilitate the new gene discovery and functional genomics study in maize.