Li Yan

Genes from the SNF2 family play important roles in transcriptional regulation, maintenance of chromosome integrity and DNA repair. This study describes the molecular cloning and characterization of cereal genes from this family. The predicted proteins exhibit a novel C-terminal domain that defines a new subfamily designated SNF2P that includes human and mouse proteins. Comparison between genomic and cDNA sequences showed that cereal Snf2P genes consisted of 17 exons, including one only 8 bp long. Two barley alleles differed by the presence of a 7.7-kb non-LTR retrotransposon in intron 6. An alternative annotation of the orthologous Arabidopsis gene would improve its similarity with the other members of the subfamily. Intron 2 was not spliced out in approximately half of the rice Snf2P mRNAs present in leaves, resulting in a premature stop codon. Transcripts from the barley and wheat Snf2P genes were found in apexes, leaves, sheaths, roots and spikes. The Snf2P genes exist as single copies on wheat chromosome arm 5AmL and in the colinear regions on barley chromosome arm 4HL and rice chromosome 3. High-density genetic mapping and RT-PCR suggest that Snf2P is not a candidate gene for the tightly linked vernalization gene Vrn2.

Purpose To investigate the reliability and accuracy of two pseudo-continuous arterial spin labeling sequences, using two-dimensional gradient-echo echo planar imaging and 3D gradient and spin echo as the readout, respectively. Materials and Methods Each sequence was performed twice 4 weeks apart on six normal control subjects, six elderly subjects with mild cognitive impairment, and one participant with Alzheimer's disease. Eight of these subjects also underwent H 215O positron emission tomography scans on the same day or proximal to their second MRI scan. The longitudinal repeatability of EPI and GRASE pCASL were evaluated with the intraclass correlation coefficient and within-subject coefficient of variation. Results The ICCs of global perfusion measurements were 0.697 and 0.413 for GRASE and EPI based pCASL respectively. GRASE pCASL also demonstrated a higher longitudinal repeatability for regional perfusion measurements across 24 regions-of-interests compared with EPI pCASL. When compared with PET, EPI pCASL showed a higher degree of spatial correlation with PET than GRASE pCASL, although the difference was not statistically significant. Conclusion The 3D GRASE pCASL offers better repeatability than 2D EPI pCASL, thereby may provide a reliable imaging marker for the evaluation of disease progression and treatment effects in MCI and early AD subjects. © 2013 Wiley Periodicals, Inc.

Growth habit varies among accessions of hexaploid wheat. The winter habit genotype requires a cold treatment to induce flowering and is generally planted in the fall. Spring habit genotypes flower in the absence of a vernalization treatment. Spring habit is conferred by a dominant allele at any of the three VRN-1 loci, but varieties carrying the VRN-A1 locus are the most frequent and usually flower earlier. To facilitate selection in populations segregating at the VRN-A1 locus and to assist in genotyping wheat accessions of unknown VRN-1 composition, a PCR-based marker for growth habit would be useful. The VRN-A1 gene was recently cloned allowing for the development of markers for growth habit. In this report, we designed primer sets specific for the VRN-A1 locus, and used them to amplify an 810-bp segment of the VRN-A1 gene between intron 4 and exon 8 from 40 spring wheat lines and 37 winter wheat lines. Three diagnostic nucleotide changes were identified that differentiated the dominant Vrn-A1 and recessive vrn-A1 alleles in 75 out of the 77 genotypes analyzed in this study. One of these differences resulted in the presence of an additional AciI restriction site in the allele for spring growth habit. This difference was exploited to develop a cleavage amplification polymorphic sequence that can be used to determine the allelic state at VRN-A1 in germplasm collections, and as a marker in backcross breeding projects. An additional pair of dominant markers was developed from a different polymorphism.