The complete DNA sequence of yeast chromosome III.

The entire DNA sequence of chromosome III of the yeast Saccharomyces cerevisiae has been determined. This is the first complete sequence analysis of an entire chromosome from any organism. The 315-kilobase sequence reveals 182 open reading frames for proteins longer than 100 amino acids, of which 37 correspond to known genes and 29 more show some similarity to sequences in databases. Of 55 new open reading frames analysed by gene disruption, three are essential genes; of 42 non-essential genes that were tested, 14 show some discernible effect on phenotype and the remaining 28 have no overt function.     

A novel abl protein expressed in Philadelphia chromosome positive acute lymphoblastic leukaemia

The Philadelphia (Ph) chromosome breakpoints in chronic myelocytic leukaemia are clustered on chromosome 22 band q11 in a 5.8-kilobase (kb) region designated bcr. The c-abl protooncogene is translocated from chromosome 9 band q34 into bcr and the biochemical consequence of this molecular rearrangement is the production of an abnormal fusion protein bcr-abl p210 with enhanced protein-tyrosine kinase activity compared to the normal p145 c-abl protein. The Ph chromosome translocation is also seen in some acute lymphoblastic leukaemias with B-cell precursor phenotypes some of which have bcr rearrangement (bcr+) and some do not (bcr-). We present evidence that the Ph+, bcr- leukaemias are associated with a novel p190 abl kinase. We propose that acute lymphoblastic leukaemias that are bcr+, p210+ are probably lymphoid blast crises following a clinically silent chronic phase of chronic myelocytic leukaemia arising in multipotential stem cells whereas bcr-, p190+ cases are de novo acute lymphoblastic leukaemias arising in more restricted precursors.     

Characterization and mapping of a white panicle mutant gene in rice

A spontaneous white panicle mutant was found from the F6 progenies of an indicajaponica cross.The mutant exhibits white stripes on its basal leaves while the panicles,rachis and pedicel are milky white colored at flowering stage.Genetic analysis in an F2 population from the cross of Zhi7/white panicle mutant indicates that the white panicle phenotype is controlled by a single recessive nuclear gene,tentatively termed as wp(t).Using microsatellite markers,the wp(t) gene was anchored between the markers of SSR101 and SSR63.9 with a map distance of 2.3 and 0.8cM,respectively,and co-segregated with the marker of SSR17 on rice chromosome 1.     

Dynamin-like protein encoded by the Drosophila shibire gene associated with vesicular traffic.

Temperature-sensitive paralysis is the most striking defect of adult Drosophila carrying the shibire mutation. This is believed to be due to a reversible block of endocytosis, which prevents membrane cycling and thus depletes synaptic vesicles. The shibire mutation also affects many tissues outside the nervous system. We have now mapped and characterized the shibire gene. A 275-kilobase yeast artificial chromosome was subcloned into cosmids, among which the gene was then located by analysing with restriction-fragment length polymorphisms. A 15-kilobase fragment of wild-type DNA rescues the mutant phenotype and the sequence of two mutant alleles show differences with wild type, demonstrating that we have isolated the shibire gene. The gene encodes a protein that is highly similar to rat dynamin, 69% of the amino-acid sequence is identical. Dynamin is a GTP-driven mechanochemical enzyme related to mammalian mx-proteins and to the yeast vps 1 gene product. Because the shibire gene product and dynamin have extensive similarity, we propose that they are cognate homologues. Dynamin causes microtubules to slide along each other in vitro and in extracts it is associated with a distinct, but so far uncharacterized, membrane fraction. In light of the shibire phenotype, we suggest that these proteins provide the motor for vesicular transport during endocytosis.     

西门塔尔牛与本地黄牛杂交试验效果分析

为了探索西门塔尔牛对凉山本地黄牛杂交改良效果,选择示范区测定了初生、6月龄和12月龄西本F1代的体重、体尺并与本地黄牛进行了比较,西本F1代牛的各项指标均比黄牛有明显的提高,并在全县29个乡得到了推广应用,经济效益显著。     

Variant (6 ; 15) translocation in a murine plasmacytoma occurs near an immunoglobulin kappa gene but far from the myc oncogene

Chromosome translocations in B-lymphoid tumours are providing intriguing insights and puzzles regarding the role of immunoglobulin genes in the activation of the myc oncogene (reviewed in refs 1, 2). The 15 ; 12 translocations found in most murine plasmacytomas and the analogous 8 ; 14 translocation in human Burkitt's lymphomas involve scissions of murine chromosome 15 (human chromosome 8) near the 5' end of the c-myc gene and subsequent fusion near an immunoglobulin heavy-chain gene. The less well characterized 'variant' translocations found in about 15% of such tumours also involve the myc-bearing chromosome band, but exchange occurs with a chromosome bearing an immunoglobulin light-chain locus--in mice, the kappa-chain locus bearing chromosome 6 (refs 3-5) and, in man, chromosome 2 (or 22), at the same band at which the kappa (or lambda) locus lies (reviewed in ref. 1). The Burkitt variant translocations involve scissions 3' of c-myc; one 8 ; 22 translocation placed the C lambda locus just 3' of c-myc, but usually the chromosome 8 breakpoint is a greater, but unknown, distance away from c-myc, more than 20 kilobases (kb) in one 8 ; 2 translocation involving the C kappa gene. Little is known about the murine 6 ; 15 translocations, although a C kappa gene cloned from one plasmacytoma (PC7183) is linked, via chromosome 12 sequences, to an unidentified region of chromosome 15 (ref. 11). We describe here the chromosome fusion region from plasmacytoma ABPC4, which displays the typical reciprocal 6;15 translocations. We find that the chromosome 6 breakpoint is near C kappa but, unlike those in the heavy-chain locus, not at a position where immunoglobulin genes normally recombine. Moreover, the chromosome 15 sequences involved in the ABPC4 translocation are not derived from the vicinity of c-myc.     

Loss of constitutional heterozygosity in colon carcinoma from patients with familial polyposis coli

Recent studies have suggested a critical role of specific gene loss in several embryonic tumours and certain adult cancers. In retinoblastoma, hemizygosity or homozygosity of a recessive mutant allele results in the loss of normal gene product, and this seems to cause the manifestation of the disorder. Familial polyposis coli (FPC) is a human autosomal dominant trait characterized by numerous adenomatous polyps of the colon and rectum, and a high incidence of colon carcinoma. Karyotype analyses have failed to detect specific deletion or translocation. We report the use of polymorphic DNA markers to look for the somatic loss of heterozygosity at specific loci. Investigation of 38 tumours from 25 FPC patients, and 20 sporadic colon carcinomas from 19 patients, revealed frequent occurrence of allele loss on chromosome 22, with some additional losses on chromosomes 5, 6, 12q and 15. The FPC gene-linked DNA probe C11p11 also detected frequent allele loss in both familial and sporadic colon carcinomas but not in benign adenomas. These results suggest the possible involvement of more than one chromosomal locus in the development of familial and sporadic colon carcinomas.     

首例t（8;20）易位的M2—ANLL白血病重组位点的初步研究

对临床上确认为Ｍ２－ＡＮＬＬ的病例，首先进行骨髓细胞染色体的核型分析，经Ｇ显带和Ｒ显色确定为ｔ（８；２０）（ｑ２２；ｐ２３）易位，是一种新的变异型，为进行分子生物学研究，分别设计引物，反转录扩增检测ＥＴＯ基因ｃＤＮＡ ３‘０端顺序和ＥＴＯ融合转录物检测为阴性，从分子水平上排除了经典的ｔ（８，２１）易位的可能性。说明了该病例为ｔ（８；２０）易位，ＥＴＯ基因受累的新变异型白血病。     

一步法合成Cs2REI5（RE=Ce,Pr）

用一步法合成了2个新化合物Cs2CeI5和Cs2PrI5，测试了这2个化合物的荧光性质，初步确定了Cs2CeI5和Cs2PrI5的结构，它们都属于四方晶系，是同型物（晶胞参数Cs2CeI5:a=1．0566nm，c=0.8729nm；Cs2PrI5:a=1.0543nm，c=0．8704nm）．并且还用XANES法测定了Cs2PrI5中Pr的价态．     

Additional deletion in sex-determining region of human Y chromosome resolves paradox of X,t(Y;22) female

Whether a human embryo develops as a male or a female is determined by the presence of the Y chromosome. The sex-determining function lies entirely in interval 1A, inasmuch as most XX individuals with descended testes and normal male external genitalia carry this small region of the Y chromosome. We have localized an essential part of the sex-determining function to a portion of interval 1A, on the basis of the discovery of a female with a reciprocal Y;22 translocation and part of 1A deleted at the translocation breakpoint. Recently, a paradox has arisen with the report of four partially masculinized XX individuals who carry only a portion of interval 1A--a portion that does not overlap the deletion in the X,t(Y;22) female. These recent findings imply that the sex-determining function lies in the portion of 1A present in the four XX intersexes and not in the portion deleted in the X,t(Y;22) female. To explain the X,t(Y;22) individual, it was proposed that she was female because of a chromosomal position effect or delayed development of the gonadal soma. Here we report that the X,t(Y;22) female has a deletion of a second portion of interval 1A--a portion corresponding closely to that present in the XX intersexes. This resolves the apparent contradiction. Nonetheless, phenotype-genotype correlations suggest that two or more genetic elements in interval 1A may contribute to the sex-determining function of the Y chromosome. The X,t(Y;22) female lacks the ZFY gene but does not exhibit the complex phenotype known as Turner's syndrome, arguing against the hypothesis that ZFY is the Turner's syndrome gene on the Y chromosome.     

Correlation between a DNA restriction fragment length polymorphism and C4A6 protein

The fourth component of complement (C4) in man, is coded for by two separate but closely linked loci (C4A and C4B) within the major histocompatibility region (MHC), on the short arm of chromosome 6. Like class I and II loci of this region, the C4 genes are highly polymorphic with more than 30 alleles, including null alleles, assigned to the two loci. This extensive polymorphism, based mainly on electrophoretic mobility, provides a useful marker for studies of disease susceptibility. Several disorders, including systemic lupus erythematosus and type I diabetes, show associations with C4 phenotypes. We have used the technique of Southern with a C4 specific probe to examine the genomic DNA of individuals typed for C4 by protein electrophoresis. We have identified 10.7 and 3.8 kilobase (kb) BglII restriction fragments in each of 9 unrelated individuals with a C4A6 allele, and in none of 22 unrelated individuals in whom this allele was not expressed. This clear correlation of restriction fragment length polymorphism with C4 phenotype provides a precise basis for analysis of C4 polymorphism. It is likely to be of value in clinical investigations of autoimmune disease.