Structural Changes of 2V Chromosome of Haynaldia villosa Induced by Gametocidal Chromosome 3C of Aegilops triuncialis

Haynaldia villosa （2n=2X= 14, VV）, a relative of wheat, plays important roles in wheat improvement mainly owing to its disease resistance. Powdery mildew resistance gene Pm21 has been successfully transferred into wheat by Cytogenetic Institute, Nanjing Agricultural University, China, and is widely used in the current wheat breeding programs. In this research, our objective is to further transfer and utilize the beneficial genes such as eye-spot resistance, yellow rust resistance, and gene of the tufted bristles on the glume ridge （a remarkable morphology） mapped on 2V of Haynaldia villosa. A disomic addition line with gametocidal chromosome 3C ofAegilops triuncialis added in Norin-26 was crossed to the wheat-H, villosa disomic substitution 2V（2D） and the hybrid F1 was then self-crossed. Chromosome C-banding, genomic in situ hybridization （GISH）, and meiotic analysis in combination with molecular markers were applied to detect the chromosome variations derived from hybrids Fz and F3. To date, four translocations including one small segmental translocation T6BS·6BL-2VS, two whole arm translocations （preliminarily designed as T3DS·2VL and T2VS.7DL） and one intercalary translocation T2VS·2VL-W-2VL, one deletion Del. 2VS·2VL-, one monotelosomic Mt2VS, and one isochromosome 2VS·2VS line have been developed and characterized. One wheat SSR marker Xwmc25.120 tagging 2VS and one wheat STS marker NAU/STSBCD135-1 （2BL） tagging 2VL were successfully used to confirm the alien chromosome segments involved in the seven lines. The tufted bristles on the glume ridge appeared in lines T2VS-7DL, Mt2VS, 2VS-2VS as well as the parent DS2V（2D）, whereas in T3DS·2VL, this trait did not appear. The gene controlling the tufted bristles was located on 2VS. Gametocidal chromosome 3C ofAegilops triuncialis could successfully induce chromosome 2V structural changes.

CHROMOSOME 3 MAY HARBOR MULTIPLE TUMOR SUPPRESSOR GENES ASSOCIATED WITH PRIMARY GLIOBLASTOMA MULTIFORME

Objective: To investigate whether deletion of chromosome 3 is involved in the carcinogenesis of primary glioblastoma multiforme (GBM) and to localize the possible common deletion region in the aforementioned chromosome. Methods: PCR based microsatellite polymorphism analyses were performed to detect loss of heterozygosity (LOH). Twenty-three loci on chromosome 3 were examined in 20 cases of GBM. Fluorescence-labeled primers and Perkin Elmer 377 DNA Sequencer were applied. Results: 50% informative cases of GBM displayed LOH on chromosome 3. 50% of informative cases displayed LOH on 3q and 35% on 3p. 25.6% of informative loci showed LOH in our series, in which frequent LOH were observed in the chromosomal region from loci D3S1614 (42.9%) to D3S1565 (35.3%) on 3q24–27 and at loci D3S1569 (35.3%) on 3q22–23 and D3S1289 (33.3%) on 3p14.1–14.3. Conclusion: Loss of genetic material on chromosome 3 may play an important part in the tumorigenesis of GBM. The chromosomal regions from loci D3S1614 to D3S1565 on 3q24–27 and at loci D3S1569 on 3q22–23 and D3S1289 on 3p14.1–14.3 are potential sites for novel tumor suppressor genes associated with GBM.

Alterations of chromosome 3p in 24 cases of gastrinomas and their correlations with clinicopathological and prognostic features

Purpose::The pathogenesis of gastrinomas is largely unknown,and there is a lack of reliable genetic determinants that are useful to distinguish malignant and benign forms of this tumor or predict the prognosis of patients with this disease.Loss of heterozygosity(LOH)on chromosome 3p is reported to occur in pancreatic neuroendocrine tumors(PNETs)as well as in non-PNETs and its presence is reported to correlate with tumor prognosis in non-endocrine tumors.However,little data are available from prospective studies on gastrinomas.Experimental design::We assessed occurrence of 3p LOH in 24 gastrinomas and correlated its presence with tumor biological behavior and other clinicopathological features of gastrinomas.Results::Either 3p LOH or microsatellite instability involving 3p occurred in 11 of 24 tumors(46%).Seven(29%)gastrinomas had 3p LOH.Of the 7 gastrinomas with 3p LOH,5(71%)had 3p12 LOH with the marker D3S2406,which was the shortest region of highest overlap(SRO).Chromosome 3p LOH was not associated with aggressive biological behavior of gastrinomas or with poor prognosis of patients with gastrinoma.Similarly,3p12 LOH(SRO)was not correlated with aggressive growth of tumors and/or liver metastases.Conclusion::Gastrinomas have a relative high frequency of 3p12 LOH suggesting this area may harbor putative tumor suppressor gene(s),which may play a role in the tumorigenesis,but not aggressiveness,of a subset of these tumors.

Relationship Between Gene-Phenotype and Clinical Manifestations of Chromosomal Copy Number Variations Indicated by Non-Invasive Prenatal Testing

Objective:To analyze the clinical value of non-invasive prenatal testing(NIPT)in detecting chromosomal copy number variations(CNVs)and to explore the relationship between gene expression and clinical manifestations of chromosomal copy number variations.Methods:3551 naturally conceived singleton pregnant women who underwent NIPT were included in this study.The NIPT revealed abnormalities other than sex chromosome abnormalities and trisomy 13,18,and 21.Pregnant women with chromosome copy number variations underwent genetic counseling and prenatal ultrasound examination.Interventional prenatal diagnosis and chromosome microarray analysis(CMA)were performed.The clinical phenotypes and pregnancy outcomes of different prenatal diagnoses were analyzed.Additionally,a follow-up was conducted by telephone to track fetal development after birth,at six months,and one year post-birth.Results:A total of 53 cases among 3551 cases showed chromosomal copy number variation.Interventional prenatal diagnosis was performed in 36 cases:27 cases were negative and 8 were consistent with the NIPT test results.This indicates that NIPT’s positive predictive value(PPV)in CNVs is 22.22%.Conclusion:NIPT has certain clinical significance in screening chromosome copy number variations and is expected to become a routine screening for chromosomal microdeletions and microduplications.However,further interventional prenatal diagnosis is still needed to identify fetal CNVs.

Identification of KASP markers and putative genes for pre-harvest sprouting resistance in common wheat(Triticum aestivum L.)

Common wheat(Triticum aestivum L.)is the most important crop in the world and a typical allopolyploid with a large and complex genome.Pre-harvest sprouting(PHS)leads to a significant reduction in grain quality worldwide.PHS is a complex trait with related QTL located on different chromosomes.However,the study of markers and genes related to PHS resistance is limited especially for whitegrained wheat.Four pairs of near isogenic lines(NILs)from a white-grained wheat cross of Chara
DM5637B*8 targeting a major QTL for PHS resistance(Qphs.ccsu-3A.1)on wheat chromosme 3AL were genotyped using the 90K SNP Illumina iSelect array.Ten SNPs were identified,with a 75%-100%consistency between genotype and phenotype in the resistant or susceptible isolines.The 10 SNPs were converted to cost-effective kompetitive allele-specific PCR(KASP)markers.Screening of 48 wheat cultivars with different phenotypes of PHS identified four KASP markers with 81.3%-85.4%conformity between genotype and phenotype.Further investigation revealed that the four SNPs(BS00022245_51,Kukri_c49927_151,BS00022884_51 and BS00110550_51)corresponding to the four validated KASP markers are residing in three independent genes(TraesCS3A03G1072800,TraesCS3A03G1072400,TraesCS3A03G1071800)close to each other with a distance of 4.28-4.48 Mb to the targeted QTL.These three annotated genes have potential functions related to PHS resistance.Our study revealed that combined use of NILs and the 90K SNP chip is a powerful approach for developing KASP markers and mining functional genes in wheat.The KASP markers for PHS resistance on chromosome 3AL are useful for high-throughput evaluation and marker-assisted selection,and the three identified genes could lead to a better understanding of the genetic pathways controlling PHS.

Integrative Identification by Hi‑C Revealed Distinct Advanced Structural Variations in Lung Adenocarcinoma Tissue

Advanced three-dimensional structure variations of chromatin in large genome fragments,such as conversion of A/B compartment,topologically associated domains(TADs)and chromatin loops are related closely to occurrence of malignant tumors.However,the structural characteristics of lung cancer still remain uncovered.In this study,we used high-throughput chromosome(Hi-C)conformation capture technology to detect the advanced structural variations in chromatin of two nonsmoking lung adenocarcinoma(LUAD)tumor and paired normal tissues.The results indicate that significant chromatin variations are detected in tumor tissues compared with normal tissues.At compartment scale,the main conversion type of compartment is A→B in tumor tissues,which are concentrated mainly on chromosome 3(Chr3)(33.6%).A total of 216 tumor-specific TADs are identified in tumor tissues,which are distributed mainly in Chr1(19),Chr2(15)and Chr3(17).Forty-one distinct enhancer-promoter loops are observed in tumor tissue,which are associated closely to tumor-related pathways including mitogen-activated protein kinase(MAPK),Phosphatidylinositol-3-kinase-Protein kinase B(PI3K-AKT),Ras,Wnt and Ras1.The most important observation in this study is that we identify five important genes(SYT16,NCEH1,NXPE3,MB21D2,and DZIP1L),which are detected in both A→B compartment,TADs and chromatin loops in tumor samples,and four of these genes(NCEH1,NXPE3,MB21D2,and DZIP1L)locate on q arm of Chr3.Further gene expression and invasion experiment analysis show that NCEH1,MB21D2 and SYT16 are involved in the tumor development.Thus,we provide a comprehensive overview of advanced structures in LUAD for the first time and provide a basis for further research on the genetic variation of this tumor.