Heterozygosity and ethnic variation in Japanese platelet proteins

Sixty-two polypeptides visualized on silver-stained two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) preparations of platelets from 85 Japanese subjects, in total 5,252 spots, have been scored for genetic variation. Inherited variants of 11 of the polypeptides were recognized; the index of heterozygosity was 2.4%±0.2%. Thus far, 10 genetic polymorphisms identified by 2-D PAGE of plasma, erythrocytes, or platelets have been identified in both Japanese and Caucasian subjects. A comparison of allele frequencies reveals four significant ethnic differences. We also observed four polypeptides exhibiting a low frequency polymorphism in one group but not in the other, as well as three polymorphisms in Caucasians for which no counterpart polypeptide has thus far been recognized in the Japanese group and, vice versa, 11 such polymorphisms in Japanese. Although a similar comparison of 7 enzyme polymorphisms studied with one-dimensional electrophoresis (1-D E) in the same populations revealed a relatively higher number of significant ethnic differences, evidence is presented that this is due primarily to the greater number of 1-D E observations entering into the calculation. It is argued that this similarity in the frequency of ethnic differences among the polypeptides studied by 2-D PAGE and by 1-D E is further evidence that the proteins revealed by 2-D PAGE do not differ greatly in their response to the interplay of mutation, selection, and drift from those revealed by 1-D E studies of plasma proteins and erythrocyte enzymes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47621/1/439_2004_Article_BF00291224.pd

The estrogen receptor-α A908G (K303R) mutation occurs at a low frequency in invasive breast tumors: results from a population-based study

INTRODUCTION: Evidence suggests that alterations in estrogen signaling pathways, including estrogen receptor-α (ER-α), occur during breast cancer development. A point mutation in ER-α (nucleotide A908G), producing an amino acid change from lysine to arginine at codon 303 (K303R) results in receptor hypersensitivity to estrogen. This mutation was initially reported in one-third of hyperplastic benign breast lesions, although several recent studies failed to detect it in benign or malignant breast tissues. METHODS: We screened 653 microdissected, newly diagnosed invasive breast tumors from patients in the Carolina Breast Cancer Study, a population-based case-control study of breast cancer in African American and white women in North Carolina, for the presence of the ER-α A908G mutation by using single-strand conformational polymorphism (SSCP) analysis and (33)P-cycle sequencing. RESULTS: We detected the ER-α A908G mutation in 37 of 653 (5.7%) breast tumors. The absence of this mutation in germline DNA confirmed it to be somatic. Three tumors exhibited only the mutant G base at nucleotide 908 on sequencing, indicating that the wild-type ER-α allele had been lost. The ER-α A908G mutation was found more frequently in higher-grade breast tumors (odds ratio (OR) 2.83; 95% confidence interval (CI) 1.09 to 7.34, grade II compared with grade I), and in mixed lobular/ductal tumors (OR 2.10; 95% CI 0.86 to 5.12) compared with ductal carcinomas, although the latter finding was not statistically significant. CONCLUSION: This population-based study, the largest so far to screen for the ER-α A908G mutation in breast cancer, confirms the presence of the mutant in invasive breast tumors. The mutation was associated with higher tumor grade and mixed lobular/ductal breast tumor histology

Segregation distortion of wild-type alleles at the Machado-Joseph disease locus: a study in normal families from the Azores islands (Portugal)

Machado-Joseph disease (MJD) is caused by an expansion of a triplet repeat with a CAG motif at the ATXN3 gene. The putative segregation ratio distortion (SRD) of alleles can play an important role in the non-Mendelian behaviour of triplet repeat loci. To study the stability and infer the segregation patterns of wild-type MJD alleles, the size of the (CAG)(n) tract was analysed in 102 normal sibships, representing 428 meioses. No mutational events were detected during the transmission of alleles. Segregation analysis showed that the smaller alleles were preferentially transmitted (56.9%). Considering maternal meioses alone, such preference was still detected (55.7%) but without statistical significance. A positive correlation was observed for the difference in length between the two alleles constituting the transmitters' genotype (D) and the frequency of transmission of the smaller alleles. The results suggest that small D values are not enough to modify the probability of allele transmission. When transmissions involving genotypes with D <or= 2 were excluded, SRD in favour of the smaller allele became significant for both maternal and paternal transmissions. Therefore, the genotypic composition of the transmitters in a sample to be analysed should influence the ability to detect SRD, acting as a confounding factor.This work was supported by ‘‘Projecto Regional Integrado— DMJ (PRI-DMJ)’’ (funded by Regional Government of the Azores), ‘‘Construyendo una Bio-Región Europea—Biopolis’’ (05/MAC/2.3/ C14, funded by PIC Interreg III B, Azores—Madeira—Canarias) and MANSEEBMO (MI.2.1/004/2005, funded by ‘‘Direcção Regional da Ciência e Tecnologia’’). CB (SFRH/BD/21875/2005) is a recipient of a Ph.D. grant, and RM (SFRH/BPD/32473/2006) and CS (SFRH/BPD/ 20944/2004) are postdoctoral fellows from ‘‘Fundação para a Ciência e a Tecnologia’’ (FCT)

Development of a new marker system for identifying the complex members of the low-molecular-weight glutenin subunit gene family in bread wheat (Triticum aestivum L.)

Low-molecular-weight glutenin subunits (LMW-GSs) play an important role in determining the bread-making quality of bread wheat. However, LMW-GSs display high polymorphic protein complexes encoded by multiple genes, and elucidating the complex LMW-GS gene family in bread wheat remains challenging. In the present study, using conventional polymerase chain reaction (PCR) with conserved primers and high-resolution capillary electrophoresis, we developed a new molecular marker system for identifying LMW-GS gene family members. Based on sequence alignment of 13 LMW-GS genes previously identified in the Chinese bread wheat variety Xiaoyan 54 and other genes available in GenBank, PCR primers were developed and assigned to conserved sequences spanning the length polymorphism regions of LMW-GS genes. After PCR amplification, 17 DNA fragments in Xiaoyan 54 were detected using capillary electrophoresis. In total, 13 fragments were identical to previously identified LMW-GS genes, and the other 4 were derived from unique LMW-GS genes by sequencing. This marker system was also used to identify LMW-GS genes in Chinese Spring and its group 1 nulli–tetrasomic lines. Among the 17 detected DNA fragments, 4 were located on chromosome 1A, 5 on 1B, and 8 on 1D. The results suggest that this marker system is useful for large-scale identification of LMW-GS genes in bread wheat varieties, and for the selection of desirable LMW-GS genes to improve the bread-making quality in wheat molecular breeding programmes

Seasonal Pattern of Batrachochytrium dendrobatidis Infection and Mortality in Lithobates areolatus: Affirmation of Vredenburg's “10,000 Zoospore Rule”

To fully comprehend chytridiomycosis, the amphibian disease caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd), it is essential to understand how Bd affects amphibians throughout their remarkable range of life histories. Crawfish Frogs (Lithobates areolatus) are a typical North American pond-breeding species that forms explosive spring breeding aggregations in seasonal and semipermanent wetlands. But unlike most species, when not breeding Crawfish Frogs usually live singly—in nearly total isolation from conspecifics—and obligately in burrows dug by crayfish. Crayfish burrows penetrate the water table, and therefore offer Crawfish Frogs a second, permanent aquatic habitat when not breeding. Over the course of two years we sampled for the presence of Bd in Crawfish Frog adults. Sampling was conducted seasonally, as animals moved from post-winter emergence through breeding migrations, then back into upland burrow habitats. During our study, 53% of Crawfish Frog breeding adults tested positive for Bd in at least one sample; 27% entered breeding wetlands Bd positive; 46% exited wetlands Bd positive. Five emigrating Crawfish Frogs (12%) developed chytridiomycosis and died. In contrast, all 25 adult frogs sampled while occupying upland crayfish burrows during the summer tested Bd negative. One percent of postmetamorphic juveniles sampled were Bd positive. Zoospore equivalents/swab ranged from 0.8 to 24,436; five out of eight frogs with zoospore equivalents near or >10,000 are known to have died. In summary, Bd infection rates in Crawfish Frog populations ratchet up from near zero during the summer to over 25% following overwintering; rates then nearly double again during and just after breeding—when mortality occurs—before the infection wanes during the summer. Bd-negative postmetamorphic juveniles may not be exposed again to this pathogen until they take up residence in crayfish burrows, or until their first breeding, some years later