High-resolution melting-based TILLING of γ ray-induced mutations in rice / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Targeting Induced Local Lesions IN Genomes (TILLING) is a reverse genetics strategy for the high-throughput screening of induced mutations. γ radiation, which often induces both insertion/deletion (Indel) and point mutations, has been widely used in mutation induction and crop breeding. The present study aimed to develop a simple, high-throughput TILLING system for screening γ ray-induced mutations using high-resolution melting (HRM) analysis. Pooled rice (Oryza sativa) samples mixed at a 1:7 ratio of Indel mutant to wild-type DNA could be distinguished from the wild-type controls by HRM analysis. Thus, an HRM-TILLING system that analyzes pooled samples of four M2 plants is recommended for screening γ ray-induced mutants in rice. For demonstration, a γ ray-mutagenized M2 rice population (n=4560) was screened for mutations in two genes, OsLCT1 and SPDT, using this HRM-TILLING system. Mutations including one single nucleotide substitution (G→A) and one single nucleotide insertion (A) were identified in OsLCT1, and one trinucleotide (TTC) deletion was identified in SPDT. These mutants can be used in rice breeding and genetic studies, and the findings are of importance for the application of γ ray mutagenesis to the breeding of rice and other seed crops.

Association of mitochondrial DNA variation with type 2 diabetes mellitus / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the prevalence of mitochondrial DNA (mtDNA) mutations in patients with type 2 diabetes mellitus in Hubei.</p><p><b>METHODS</b>A total of 184 cases of type 2 diabetes mellitus and 210 matched healthy controls with normal glucose tolerance were recruited for the study. The variants of mtDNA, including MIND13316 (G-->A), MIND13394 (T-->C), MTTE14693 (A-->G), MTTL1 3243 (A-->G), MTRNA1310 (C-->T) and 16189 (T-->C), were screened using PCR-restriction fragment length polymorphism (PCR-RFLP) analysis and DNA sequencing. The mutations were analyzed by mfold or tRNAscan-SE softwares.</p><p><b>RESULTS</b>The mutation rates of 3316 (G-->A), 3394 (T-->C), 14693 (A-->G) were 3.26%, 2.72% and 2.17% respectively in type 2 diabetes group, whereas in the control group, the point mutations of 3394 (T-->C) and 14693 (A-->G) were not detected, but two subjects with 3316 (G-->A) were found (0.99%). There were significant differences in mutation rates of 3394 (T-->C) and 14693 (A-->G) between the two groups (P<0.05). In 4 of 184 cases, a T to C transition at nucleotide position 14693 was uncovered for the first time. The prevalence of 16189 variant among type 2 diabetes was significantly higher that of the controls (36.9% vs 26.6%, P=0.03). Moreover, the type 2 diabetes with 16189 variant showed higher fasting serum insulin level and higher HOMA-IR level than those without 16189 variant; stepwise multiple regression analysis showed the 16189 variant was an independent factor contributing to HOMA-IR (R(2)=0.043, P=0.037). Secondary structure prediction revealed that there were differences in 3394 T-->C vs wild-type ND1 protein and in 14693 A-->G vs wild-type tRNA(Glu) protein.</p><p><b>CONCLUSION</b>The mutations of 3394 (T-->C) and 14693 (A-->G) may contribute to the genetic predisposition to type 2 diabetes; 16189 (T-->C) variant is associated with insulin resistance and risk factor of diabetes.</p>

Development of a nylon membrane chip for rapid detecting the diabetes-associated 45 mutant loci in mitochondrial DNA / 中华检验医学杂志

Objective To develop a nylon membrane chip for rapid and systematic detection of the diabetes-associated 45 mutant loci in mitochondrial DNA(mtDNA).Methods The mutant-and wild-type probes were designed for detection of 45 mutant loci in mtDNA with Primer Premier 5.0 and NCBI BLAST softwares and the 90 probes with 8 poly T were immobilized on the Hybond N~+ nylon membranes which were treated with 5?SSC Buffer by UV-crosslinking;Then asymmetric PCR was employed to obtain the target single strand DNA(ssDNA).The PCR products were labeled with biotin after purification.NBT/BCIP was used as substrate that yields a very intense purple signal followed by AP-avidin,and the signals were observed in 24 samples with known sequences to evaluate the chips,each sample was repeatedly measured three times.Results The specific target fragments of 45 loci can be amplified under the same condition with nine sets of primers.The annealing temperatures of the wild-type [(59.01?1.42)℃] and mutant-type [(59.34?1.29)℃ ] probes are so close(t=1.046,P =0.301)that hybridization can be performed at the same temperature.The spots on the membrane chip are distinct,regular and well-distributed.The results of positive-and negative-control are perfect.The signals of negative probes and the background are similar.The results of chip were nearly concordant with that of DNA sequences(?~2=113.132,Kappa value =0.888,P = 0.000)except for T16189C mutant.Conclusions We have successfully developed a nylon membrane chip for rapid and systematic detection of the diabetes-associated 44 mutant loci in mtDNA.It could be used for screening for diabetic patients and high-risk people.

Predisposition of type 2 diabetes mellitus in elderly patients with mitochondrial DNA base variants / 中华老年医学杂志

Objective To investigate the relationship between the genetic predisposition to type 2 diabetes mellitus(T2 DM)and mitochondrial DNA base variants in elderly patients.Methods PCR restriction fragment length polymorphism(PCR-RFLP)analysis was used to screen base variants at position 3243 and 3426 of mitochondrial DNA in 186 elderly cases with T2 DM and 170 healthy controls,and DNA sequence was confirmed.Results No carrier of 3243 A→G variant or 3426 A→G variant was found in both groups,however there was 1 case with 3290 T→C variant in diabetic group.Conclusions No significantly association was found between mitochondrial DNA 3243 or 3426 base variants and the predisposition of type 2 diabetes mellitus in elderly patients.