ENU诱导获得一种短尾小鼠及其突变基因的初步定位

用一种化学诱变剂ENU(乙酰基亚硝基脲 )腹腔注射 3 0只 8～ 1 0周龄C5 7BL 6J(简称B6)雄鼠 (G0代 ) ,6周后与同品系正常母鼠配种繁殖后代 (G1代 )小鼠 3 5 1只。对其后代进行筛选获得一种可遗传的显性短尾突变小鼠。为了定位该突变基因 ,运用平均分布于B6和DBA 2 (简称D2 )小鼠常染色体而在这两者间又有差异的 3 9个微卫星对突变小鼠的 (D2×B6)F1代短尾突变小鼠回交D2得到的有短尾表型的[(B6×D2 )F1×D2 ]F2 代小鼠进行基因组扫描。反向运用经典的位置候选基因法 ,将短尾突变基因定位于 1 7号染色体 ,与D1 7Mit3 3的LOD值为 9 0 8。选用该染色体上与短尾表型相关基因Brachyury (T)最近的微卫星D1 7Mit1 43引物扩增 ,在 1 0 9只F2 代短尾小鼠中未发生一例交换 ,表明Brachyury基因是本例短尾突变强有力的候选基因。     

两种白斑小鼠突变基因的染色体定位

以本中心ENU诱变获得的两种白斑突变小鼠W-4Bao与Kitl-1Bao为研究对象[均为C57BL/6J(B6)背景],遗传试验表明它们都为单基因显性遗传,W-4Bao及Kitl-1Bao突变基因纯合子小鼠的表型分别为全白色及“黑头白”;将白斑杂合子小鼠与DBA/2(D2)交配获得具有白斑表型的F1小鼠,F1小鼠再回交D2繁殖[(B6×D2)F1×D2]F2小鼠,利用微卫星标记对F2代小鼠进行连锁分析。结果发现W-4Bao与微卫星D5Mit356、D5Mit308之间的LOD值分别为56.82、51.50,从而把该突变基因定位于第5号染色体D5Mit356与D5Mit308之间;Kitl-1Bao与微卫星D10Mit70、D10Mit68之间的LOD值分别为27.37、21.20,从而把该突变基因定位于第10号染色体上D10Mit70与D10Mit68之间。经过检索小鼠基因组数据库确认它们的候选基因分别为kit及kitl。     

乙烷基亚硝基脲诱变获得两例新的被毛突变小鼠

采用乙烷基亚硝基脲 (Ethylnitrosourea ,ENU)诱变获得人类疾病的小鼠模型。用 1 0 0mg/KgENU腹腔注射 1 8只 8- 1 0周龄的雄性DBA小鼠 (G0 ) ,每周一次共三次 ;将在后代小鼠 (G1 )筛查到的突变个体与同品系配种 ,若异常表型传代则可能为显性突变 ;选择表型正常的G1 雄鼠与C5 7BL/ 6配种得F1 ,将F1 随机互交得到F2 ,依据F2 是否有突变鼠出现确定可能存在的隐性突变。结果表明 ,在 35 2只G1 小鼠中 ,1 4只出现异常表型 ,但均未传代 ;对 30只G1 雄鼠的隐性遗传试验获得 2只稀毛突变小鼠 ,均表现为被毛稀疏、幼鼠生长缓慢     

snthr-1Bao稀毛小鼠突变基因的精确定位及克隆鉴定

snthr-1Bao稀毛小鼠足本实验室培育的呈单基因隐性遗传的突变系小鼠,突变基因已被初步定位于第9号染色体末端;为了精确定位并鉴定snthr-1Bao稀毛小鼠的突变基因,将(C57BL/6Jxsnthr-1Bao)F1代互交繁殖F2代小鼠4400余只,其中稀毛小鼠1100只,并在2个微卫星、35个可能的简单序列重复标记(simple sequence repeat,SSR)及3个酶切扩增多态性序列(cleaved amplified polymorphic sequences,CAPS)标记中找到4个合适的基因组标记.利用这些标记及F2代稀毛小鼠将突变基因精确定位到第9号染色体距着丝粒117.763 kb及119.129kb之间1.367Mb的范用内,在其问的21个基因中确定Plcdl为稀毛突变的强力候选基因.通过对基因组的直接测序,发现snthr-1Bao稀毛小鼠基因组上有一个14883bp的缺失,这一缺失包含了Plcd1基因的4-15号外显子及Vill基因的10-19号外显子.推测极可能是Plcdl基因缺失导致snthr-1Bao小鼠出现稀毛表型.     

snthr^-1Bao佃彻稀毛小鼠突变基因的精确定位及克隆鉴定

snthr^-1Bao稀毛小鼠是本实验室培育的呈单基因隐性遗传的突变系小鼠,突变基因已被初步定位于第9号染色体末端;为了精确定能并鉴定snthr^-1Bao稀毛小鼠的突变基因,将（C57BL／6J×snthr^-1Bao）F1代互交繁殖F2代小鼠4400余只,其中稀毛小鼠1100只,并在2个微卫星、35个可能的简单序列重复标记（simplesequence repeat,SSR）及3个酶切扩增多态性序列（Cleaved amplified polymorphic sequences,CAPS）标记中找到4个合适的基因组标记。利用这些标记及F2代稀毛小鼠将突变基因精确定位到第9号染色体距着丝粒117．763kb及119．129kb之间1．367Mb的范围内,在其间的21个基因中确定Plcdl为稀毛突变的强力候选基因。通过对基因组的直接测序,发现snthr^-1Bao稀毛小鼠基因组上有一个14883bp的缺失,这一缺失包含了Plcdl基因的4-15号外显子及Vill基因的10—19号外显子。推测极可能是Plcdl基因缺失导致snthr^-1Bao小鼠出现稀毛表型。     

腹侧黄斑小鼠的部分特征及其突变基因的染色体定位

腹侧黄斑小鼠(VYSlac)是在B6小鼠繁殖生产过程中被发现、分离的突变系小鼠,呈单基因显性遗传,其头颈及躯干的腹侧为黄色。VYSlac腹部表皮多巴(+)黑色素细胞及毛囊内黑色素较其背景品系B6少;腹部毛发颜色浅黄、多数无黑色素沉积,但结构正常。通过微卫星标记与48只F2小鼠(VYSlacD2F1回交D2)的连锁分析发现,突变基因与D2Mit229间的LOD值为5.79,确定连锁。随后,在突变基因附近反复多次筛选新的微卫星或SNP标记,通过对196例F2小鼠的多次连锁分析,将突变基因所在区域缩小到rs13476833(距着丝粒149804749bp)与rs27310903(距着丝粒155060764bp)间约5256015bp的范围内。     

大麦多节分枝多穗矮秆突变基因的染色体定位

采用全套染色体形态状标记系,对大麦多性状综合突变基因ｍｂｄ进行了染色体定位,结果表明,ｍｂｄ在大麦的１Ｈ染色上处于矮秆基因ｂｒ和裸粒基因ｎ之间,可能由１Ｈ的短臂携带,其中,与短臂上ｂｒ之间的遗传距离为２９．７ｃＭ,与长臂上ｎ的遗传距离是４２ｃＭ。     

ENU诱变获得一例巨结肠症小鼠及其突变基因的染色体定位

采用化学诱变剂乙酰基亚硝基脲(N-ethyl-N-nitrosourea,ENU)获得一种可遗传的腹部白斑突变杂合子小鼠,将该杂合子小鼠互交后获得具有花斑表型的突变纯合子小鼠,进一步研究表明突变纯合子小鼠表现为严重的巨结肠表型。肠全标本乙酰胆碱酯酶组织化学染色显示突变纯合子小鼠巨结肠段神经节细胞缺失。为定位该基因,利用微卫星标记(B6×D2)对F1互交获得的F2突变纯合子小鼠进行基因组扫描,初步将该突变基因定位于小鼠第14号染色体。     

转基因小鼠和基因突变小鼠微卫星不稳定性分析

目的探讨微卫星在转基因和基因突变小鼠中的变化,为基因修饰和遗传突变动物的遗传检测和表型分析提供理论依据和技术手段。方法根据文献报道,从GenBank中选取198个等位基因数量多、富含多态性的微卫星位点,以野生型动物为对照,对6种近交系遗传背景的转基因小鼠和5种自然基因突变的近交系小鼠进行微卫星多态性检测,选用1.5%琼脂糖凝胶电泳和STR扫描技术,比较分析微卫星不稳定性。结果共有40个微卫星位点在转基因和基因突变小鼠中表现出多态性。在基因突变小鼠中,微卫星不稳定性有55.6%(10/18)是由纯合变为杂合(Ⅰ型),有3个位点(16.6%,3/18)是纯合突变(Ⅱ型),有5个位点同时存在2种类型的突变。但是在转基因动物中,大多数的微卫星多态性为Ⅰ型突变(87.5%,28/32),只有2个位点(6.2%,2/32)是Ⅱ型突变。另外有2个位点同时存在2种类型的突变。结论基因修饰或基因突变可引起小鼠相关微卫星发生不稳定性,而且某些微卫星位点对基因改变敏感性较高。     

snthr-1Bao稀毛小鼠的生物学特性

对稀毛小鼠snthr-1Bao和对照组DBA/2小鼠的生长情况、繁殖性能、形态学和大体解剖学进行了观察.结果表明snthr-1Bao小鼠的生长发育较DBA/2小鼠迟缓,被毛异常,呈稀疏状.在繁殖学特性方面,snthr-1Bao小鼠与DBA/2小鼠相比雄性睾丸组织绝对重量和脏器系数均比DBA/2小,差异呈极显著性(P＜0.01);断奶仔数比DBA/2小鼠少,差异呈极显著性(P＜0.01).对大体解剖学特性的观察表明,两种品系小鼠的心、肝、脾、肺、肾、肾上腺、胸腺、脑等脏器的位置、形态结构无差异,但有些脏器的绝对重量和脏器系数存在品系间差异(P＜0.05或P＜0.01).血液生理指标方面两种品系小鼠相比在白细胞、嗜中性白细胞、嗜酸性粒细胞以及嗜碱细胞的数量上存在差异(P＜0.01).因此,该突变不仅影响小鼠被毛的正常生长,还影响小鼠的生长发育、繁殖性能及血液生理指标.     

Mapping and regulation of the cel genes in Erwinia chrysanthemi

Summary Chromosomal mutations of the celZ and celY genes which encode two different endoglucanases in Erwinia chrysanthemi 3937 were obtained by a three-step procedure: (i) in Escherichia coli, insertions of lacZ fusion-forming mini-Mu bacteriophages in the cel genes cloned on plasmids and screening of cel-lac fusions, (ii) Mu-mediated transduction in E. chrysanthemi of the plasmids carrying the fusions, (iii) recombinational exchange between the plasmidic mutated and the wild-type chromosomal alleles. These mutations allowed mapping of celZ between ura and pan and celY between xyl and met on the linkage map of E. chrysanthemi. The -galactosidase activity of these strains indicated that celZ is expressed in the late exponential and stationary growth phases, while celY expression is almost undetectable.     

Mapping of ecologically unfavorable territories based on human hair composition

As was shown (1), analysis of human hair on the population level and mapping of large territories using hair elemental composition are promising approaches for estimation of both the environmental situation and the population health status. In (1,2) the map of Uzbekistan (sampling in 1981) was discussed. Ten years later (1991), samples from the territory in the vicinity of the drying out Aral Sea were taken again. Samples were analyzed for 24 elements using instrumental neutron activation analysis. Comparison of the data and maps drawn for 1981 and 1991 and their comparison with changes of the health status have shown that repeated mapping of territories using data on human hair elemental composition could be used in medical geography, especially for prediction of health status changes in ecologically unfavorable areas.     

Molecular analysis and mapping of two genes encoding maize glutathione S-transferases (GST I and GST II)

Maize glutathione S-transferase (GST) isozymes are encoded by a gene family comprising at least five genes, three of which (Gst I, II andIII) have recently been isolated and sequenced. The enzymes are active as homo or heterodimers and exhibit intraspecific polymorphism including a “null” variant for the two major isoforms expressed in roots. Northern blot analyses performed on total root RNA from “null” and “plus” genotypes, usingGst I- andGst II-specific probes, indicated that theGst I gene controls the expression of the two major GST isoforms expressed in roots.Gst I andGst II were mapped by RFLP analysis using an F₂ population of 149 individuals previously characterized.Gst I was localized on the long arm of chromosome 8, while two putativeGst II loci were mapped to chromosomes 8 (70 cM fromGst I) and 10, respectively.     

Telogen elongation in the hair cycle of ob/ob mice

Alopecia impairs the physical and mental health of patients. We have previously shown that 8-week-old ob/ob mice have no reactivity to depilation, which is a stimulus that induces anagen transition in normal mice, while no hair cycle abnormalities have been reported in other studies until mice reach 7 weeks of age. Therefore, we hypothesized that ob/ob mice have abnormalities in hair cycle progression beyond 7 weeks of age. We examined 6- to 24-week-old ob/ob and 6- to 10-week-old normal mice. After acclimation, the dorsal skin was harvested and the hair cycle phase was identified histologically and immunohistochemically. Normal mice showed catagen–telogen and telogen–anagen transitions at 6 and 8–9 weeks old, respectively. In contrast, the anagen–catagen transition was observed in 7-week-old mice and the telogen phase was maintained from 10 to 24 weeks in most ob/ob mice. These results suggests that ob/ob mice are a possible model animal for telogen effluvium.     

Mapping of Rice Rf Gene by Bulked Line Analysis

A method, bulked line analysis (BLA), was developed for identificationof the RFLP markers associated with a target gene. Instead ofsegregating progenies, conventional lines sharing the same traitwere bulked by the BLA method. This method is an alternativeapproach to the identification of DNA markers linked with atarget gene. A major advantage of this method is time-savingfor genetic stock development. The advantage is very significantfor organisms having a long generation period. This method hasbeen tested by using fertility restoration of rice cytoplasmicmale sterility of wild abortive type as a target trait. A fertility-restoringgene was successfully identified by linkage with RFLP markers.This gene was mapped in the middle of the long arm of chromosome10 of the rice genome.     

Mapping of ben genes of Pseudomonas aeruginosa

Abstract Four ben genes responsible for the conversion of benzoate to catechol in Pseudomonas aeruginosa PAO have been mapped to a 4.6 kb Kpn I fragment. ben -1 and ben -4 were known to be separate genes but now ben-1508 has been found to be different from ben-2 . The two genes were distinguished by Tn 5 mutagenesis of a cosmid clone and deletion mapping. It is likely that the four genes mapped ( ben-4, ben-2, ben-1508 and ben-1 ) correspond to the previously characterized benR (regulatory gene) and benABC (benzoate dioxygenase) respectively.