Chromosome Mapping, Expression and Polymorphism Analysis of CRABP1 Gene in Pigs

Cellular retinoic acid-binding protein 1 （CRABP1） is a well-conserved member of cytosolic lipid-binding protein family. It is an important modulator of retinoic acid signaling. Long serial analysis of gene expression （LongSAGE） analysis suggested that CRABP1 gene was differentially expressed during prenatal skeletal muscle development in porcine. Here, we obtained the full-length coding region sequence and genomic sequence of the porcine CRABP1 gene and analyzed its genomic structures. Subsequently, we examined CRABP1 chromosome assignment using INRA-University of Minnesota 7 000 porcine radiation hybrid panel （IMpRH） and explored its tissue distribution in adult Tongcheng pigs and dynamical expression profiles in prenatal skeletal muscle （33, 65 and 90 days post coitus, dpc） from Landrace （lean-type） （described as L33, L65 and L90） and Tongcheng pigs （obese-type） （described as T33, T65 and T90）. The CRABPI gene was mapped to chromosome 7ql 1-q23 and closely linked to the microsatellite marker SWR1928. Quantitative real-time PCR showed that CRABP1 mRNA was highly expressed in lung and stomach, moderately expressed in placenta and uterus, and weakly expressed in other tissues. Moreover, CRABP1 gene was down-regulated during prenatal skeletal muscle development in both Landrace and Tongcheng pigs and it was expressed much higher in T33 than L33. Two single-nucleotide polymorphisms （SNPs） were detected by sequencing and mass spectrometry methods, allele frequency analysis indicated that g. 281 （G〉A） and g. 2992 （G〉A）were deviated from Hardy-Weinberg equilibrium in the Landrace and DLY （Duroc×（Landrace×Yorkshire）） pig breeds.

Cloning of a Resistance Gene Analog from Wheat and Development of a Codominant PCR Marker for Pm21

To Investigate the mechanism of resistance to wheat （Triticum aestivum L.） powdery mildew, suppression subtractlve hybridization was conducted between an isogenic resistant line carrying Pm21 and its recurrent parent Yangmal 5 to Isolate the resistance relative genes. A cDNA fragment specifically expressed in the resistant line was obtained and its full length was cloned by in silico cloning and RT-PCR. This gene encoded a deduced protein of 219 amino acids with a leucine-rich repeat （LRR） motif, often found In plant resistance genes, and was designated as Ta-LRR2. Ta-LRR2 had an increased expression level in the resistant line after Inoculation with Erysiphe graminis DC. f. sp. tritici Marchal. PCR analysis with different cytogenetlc stocks suggested that Ta-LRR2 was specifically associated with chromosome arms 6VS and 6AS. Linkage analysis further showed that Ta-LRR2 could be used as a resistance gene analog polymorphism marker of Pm21 for marker-assisted selection in germplasm enhancement and breeding practice. Moreover, how to Isolate Pm21 based on the Information obtained for Ta-LRR2 is discussed.