Surface properties of irreversibly sickled cells differ from those of the bulk of sickle cells Studies by partitioning in aqueous phase systems

Counter-current distribution (CCD) of red blood cells (RBC) from individuaks with homozygous sickle cell (HbSS) disease in a charge-sensitive aqueous dextran-poly(ethylene glycol) phase system, which fractionates cells on the basis of surface properties, indicates that the percentage of irreversibly sickled cells (ISC) increases and the percentage of reticulocytes decreases with increasing cell partition ratios. The high partition ratios of ISC correspond to those of older RBC when RBC from normal individuals are subjected to CCD. Our results thus indicate that ISC differ in surface properties from those of the bulk of sickle RBC (including reticulocytes) in the population and that the difference is, most likely, charge-related. While the question as to whether ISC are indeed old cells has not yet been unequivocally answered, this view finds support in the fact that the independent parameters of ISC surface properties, as reflected by partition ratios, and densities correlate as they do in older RBC from normal individuals.     

Targeted sequencing and integrative analysis of 3,195 Chinese patients with neurodevelopmental disorders prioritized 26 novel candidate genes

Neurodevelopmental disorders(NDDs) are a set of complex disorders characterized by diverse and cooccurring clinical symptoms. The genetic contribution in patients with NDDs remains largely unknown.Here, we sequence 519 NDD-related genes in 3,195 Chinese probands with neurodevelopmental phenotypes and identify 2,522 putative functional mutations consisting of 137 de novo mutations(DNMs) in 86 genes and 2,385 rare inherited mutations(RIMs) with 22 X-linked hemizygotes in 13 genes, 2 homozygous mutations in 2 genes and 23 compound heterozygous mutations in 10 genes. Furthermore, the DNMs of16,807 probands with NDDs are retrieved from public datasets and combine in an integrated analysis with the mutation data of our Chinese NDD probands by taking 3,582 in-house controls of Chinese origin as background. We prioritize 26 novel candidate genes. Notably, six of these genes d ITSN1, UBR3, CADM1,RYR3, FLNA, and PLXNA3 d preferably contribute to autism spectrum disorders(ASDs), as demonstrated by high co-expression and/or interaction with ASD genes confirmed via rescue experiments in a mouse model. Importantly, these genes are differentially expressed in the ASD cortex in a significant manner and involved in ASD-associated networks. Together, our study expands the genetic spectrum of Chinese NDDs,further facilitating both basic and translational research.     

Role of Smad4 (DPC4) inactivation in human cancer

The tumor suppressor gene Smad4 (DPC4) at chromosome 18q21.1 belongs to the Smad family, which mediates the TGFbeta signaling pathway suppressing epithelial cell growth. This review summarizes the mutational events of the Smad4 gene in human cancer. The Smad4 gene is genetically responsible for familial juvenile polyposis, an autosomal dominant disease characterized by predisposition to gastrointestinal polyps and cancer. In this syndrome, polyps are formed by inactivation of the Smad4 gene through germline mutation and loss of the unaffected wild-type allele. In pancreatic and colorectal cancer, inactivation of the Smad4 gene through homozygous deletion or intragenic mutation occurs frequently in association with malignant progression. However, mutation of this gene is seen only occasionally in the rest of human cancers. The majority of Smad4 gene mutations in human cancer are missense, nonsense, and frameshift mutations at the mad homology 2 region (MH2), which interfere with the homo-oligomer formation of Smad4 protein and the hetero-oligomer formation between Smad4 and Smad2 proteins, resulting in disruption of TGFbeta signaling. Supporting evidence for the above observation was provided by genetically manipulated mice carrying either a heterozygote of the Smad4 gene or a compound heterozygote of the Smad4 and APC genes, which develop either gastrointestinal polyps/cancer mimicking familial juvenile polyposis or progressed colorectal cancer, respectively.     

Hypertrophic cardiomyopathy: two homozygous cases with "typical" hypertrophic cardiomyopathy and three new mutations in cases with progression to dilated cardiomyopathy

About 10% of cases of hypertrophic cardiomyopathy (HCM) evolve into dilated cardiomyopathy (DCM) with unknown causes. We studied 11 unrelated patients (pts) with HCM who progressed to DCM (group A) and 11 who showed "typical" HCM (group B). Mutational analysis of the beta-myosin heavy chain (MYH7), myosin-binding protein C (MYBPC3), and cardiac troponin T (TNNT2) genes demonstrated eight mutations affecting MYH7 or MYBPC3 gene, five of which were new mutations. In group A-pts, the first new mutation occurred in the myosin head-rod junction and the second occurred in the light chain-binding site. The third new mutation leads to a MYBPC3 lacking titin and myosin binding sites. In group B, two pts with severe HCM carried two homozygous MYBPC3 mutations and one with moderate hypertrophy was a compound heterozygous for MYBPC3 gene. We identified five unreported mutations, potentially "malignant" defects as for the associated phenotypes, but no specific mutations of HCM/DCM.     

Homozygous haplotype deficiency reveals deleterious mutations compromising reproductive and rearing success in cattle

Background

Cattle breeding populations are susceptible to the propagation of recessive diseases. Individual sires generate tens of thousands of progeny via artificial insemination. The frequency of deleterious alleles carried by such sires may increase considerably within few generations. Deleterious alleles manifest themselves often by missing homozygosity resulting from embryonic/fetal, perinatal or juvenile lethality of homozygotes.

Results

A scan for homozygous haplotype deficiency in 25,544 Fleckvieh cattle uncovered four haplotypes affecting reproductive and rearing success. Exploiting whole-genome resequencing data from 263 animals facilitated to pinpoint putatively causal mutations in two of these haplotypes. A mutation causing an evolutionarily unlikely substitution in SUGT1 was perfectly associated with a haplotype compromising insemination success. The mutation was not found in homozygous state in 10,363 animals (P = 1.79 × 10⁻⁵) and is thus likely to cause lethality of homozygous embryos. A frameshift mutation in SLC2A2 encoding glucose transporter 2 (GLUT2) compromises calf survival. The mutation leads to premature termination of translation and activates cryptic splice sites resulting in multiple exon variants also with premature translation termination. The affected calves exhibit stunted growth, resembling the phenotypic appearance of Fanconi-Bickel syndrome in humans (OMIM 227810), which is also caused by mutations in SLC2A2.

Conclusions

Exploiting comprehensive genotype and sequence data enabled us to reveal two deleterious alleles in SLC2A2 and SUGT1 that compromise pre- and postnatal survival in homozygous state. Our results provide the basis for genome-assisted approaches to avoiding inadvertent carrier matings and to improving reproductive and rearing success in Fleckvieh cattle.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1483-7) contains supplementary material, which is available to authorized users.     

红鲫近交系的建立

目的应用人工雌核发育繁殖技术建立红鲫近交系.方法红鲫卵子被经紫外线照射的鲤鱼精子激活后,在0～4℃的温度下进行冷休克处理30min,再在常温下静水孵化;以红体色为遗传标记,在连续2代雌核发育子代中选择二倍体红鲫,放置水泥池中常规饲养;用同样的人工雌核发育繁殖技术进行保种,随机交配繁殖1～2代供应实验;用常规方法测量形态学指标.结果红鲫卵子激活率在91%以上;实验组2中摄食期仔鱼成活率为15.20%,80%的成鱼为二倍体红鲫,其中有较高比例的遗传上真实的雄性个体.鳞式主要为27(5)/(6)28;鳍式主要为D.i,17～18;A.i,6;V.i,7～8;P.i,15～16;C.24～25;其他外部形态指标与封闭群红鲫近似.结论本实验建立的人工雌核发育繁殖技术,设备要求简单,操作安全可靠,并且省时节资,完全能够用于培育鱼类近交系,本实验结果完全可以满足育种繁殖的要求;所获得的二倍体红鲫,经同工酶电泳等检测,被证实是纯合的,具备鱼类近交系品系特征;出现遗传上真实的雄性个体是正常的.     

A Simple and Rapid PCR-based Procedure for Identifying Homozygous Transgenic Rice Plants

We present a simple and rapid method for screening second-generation transgenic rice plants (T₁) to identify homozygous plants. The plasmid (pfd11) used for rice transformation contains a partially deleted cytochrome c gene (cyc) for comparing with the endogenous cyc for copy number. After polymerase chain reaction (PCR) amplification of a segment of the cyc in transgenic rice DNA followed by agarose gel electrophoresis, two specific bands are obtained. The upper band represents the endogenous cyc, and the lower band represents the partially deleted cyc in the transgene. The first-generation plants (T₀) that harbor a single copy of the transgene are selected based on the fact that the density of the lower band is half as dense as the upper band. Next, only plants harboring a single copy of the transgene are advanced to the second generation (T₁). The same PCR procedure is used again, and homozygous T₁ plants are easily identified from samples in which the intensity of the two bands is the same.     

水稻纯合胚致死突变研究

以ＥＭＳ的处理并结合组织培养技术成功地获得胚致死突变的纯合再生植株。该植株生长发育正常,除种子无发芽能力外,纯合突变体的一切性状均与亲本品种表现一致。观察到胚败育的各种表现：（１）仅具有一个球形胚。（２）完全没有胚器的分化。（３）仅具胚根的分化而无胚芽的分化。（４）胚芽分化不完全。（５）胚芽与胚根之间没有输导组织相连接或者输导组织发育不完全等等。（纯合突变体×正常品种）杂种当代的种子（Ｆ１）发芽正常,而由Ｆ１及Ｒ１植株上所产生的种子（Ｆ２及Ｒ２）约有３／４具发芽能力,而１／４无发芽能力。统计分析的结果表明胚致死突变受隐性单基因控制。据我们所知,获得胚致死突变纯合体的成熟植株,本研究乃是首例报告,至少在水稻上是如此。在以利用无融合生殖之固定杂种优势的“一系法”杂交水稻生产的设想中,胚致死突变可作为胚乳的提供者而加以利用。     

The hybridisation of somatically chromosome-doubled dihaploid potatoes with tetraploid cultivars and the use of doubled dihaploids in genetic analysis of Solatium tuberosum

Three doubled dihaploid potatoes were hybridised with six tetraploid cultivars and the offspring examined for commercially important characters. Doubled dihaploids used as parents did not reduce the within progeny phenotypic variation for most characters below that found in material produced by intercrossing heterozygous tetraploids. They could however prove useful for improving some characters in a breeding programme. The products of the hybridisations were used to examine the genetic control of discrete variables such as tuber skin pigmentation, tuber flesh colour, and skin russetting. Doubled dihaploids were found to be useful for such studies because they have only three out of the five possible tetraploid genotypes. Presence or absence of red tuber skin in the progenies of cv. Désirée was concluded to be due to the segregation of a dominant major gene which was simplex in the parental cultivar. The yellow flesh of Desiree was found to be recessive. On the hypothesis that russet skin was due to three complementary dominant genes, possible genotypes of the doubled dihaploids and cultivars could also be deduced.     

寻常型银屑病遗传度的研究

对临床已确诊的212例寻常型银屑病患者进行了一、二、三级亲属发病率调查, 结果表明,患者一级亲属的发病率为3.8%,对照组一级亲属发病率为0.42%,本病的遗传方式为多基因遗传,遗传度为58.2%。