Identification and cloning of GOLDEN2-LIKE1 (GLK1), a transcription factor associated with chloroplast development in Brassica napus L.

Photosynthesis is the process by which dry matter accumulates, which affects rapeseed yield. In this study, we identified GOLDEN2-LIKE1 (GLK1), located on chromosome A07 and 59.2 kb away from the single nucleotide polymorphism marker SNP16353A07, which encodes a transcription factor associated with the rate of photosynthesis in leaves. We then identified 96 GLK1 family members from 53 species using a hidden Markov model (HMM) search and found 24 of these genes, which were derived from 17 Brassicaceae species. Phylogenetic analysis showed that 24 Brassicaceae proteins were classified into three subgroups, named the Brassica family, Adenium arabicum, and Arabidopsis. Using homologous cloning methods, we identified four BnaGLK1 copies; however, the coding sequences were shorter than the putative sequences from the reference genome, probably due to splicing errors among the reference genome sequence or different gene copies being present in the different B. napus lines. In addition, we found that BnaGLK1 genes were expressed at higher levels in leaves with more chloroplasts than were present in other leaves. Overexpression of BnaGLK1a resulted in darker leaves and siliques than observed in the control, suggesting that BnaGLK1 might promote chloroplast development to affect the rate of photosynthesis in leaves. These results will help to elucidate the mechanism of chloroplast biogenesis by GLK1 in B. napus.

Expression of transforming growth factor-ß1 in neonatal rats with hyperoxia-induced bronchopulmonary dysplasia and its relationship with lung development.

The aim of this study was to detect the expression of transforming growth factor-ß1 (TGF-ß1) in neonatal rats with hyperoxia-induced bronchopulmonary dysplasia (BPD) and to explore its relationship with lung development. Forty-eight rats (2-3 days old) were randomly divided into a hyperoxia group and a control group (N = 24) which were then fed in ≥95% oxygen atmosphere and air, respectively. On the 1st, 3rd and 7th days of hyperoxia exposure, morphological changes of lung tissues were observed under an optical microscope. TGF-ß1 mRNA and protein levels in lung tissues were detected by real-time quantitative polymerase chain reaction and western blot, respectively. With increasing time of hyperoxia exposure, the hyperoxia group gradually suffered from pathological changes such as poor development of lung tissues, alveolar simplification, decrease in the number of alveoli, and hindered pulmonary microvascular development. On the 7th day of hyperoxia exposure, TGF-ß1 mRNA and protein levels (relative to b-actin) of the hyperoxia group (0.34 ± 0.19 and 0.21 ± 0.09, respectively) were significantly lower than those of the control group (0.83 ± 0.45 and 0.57 ± 0.45, respectively; P < 0.05). TGF-ß1 participates in the pathogenesis of BPD as an important regulatory factor during pulmonary vascular development.

Screening of differentially-expressed genes in the muscles of rabbit breeds with expression profile chip.

The molecular mechanism underlying muscle development in rabbits is not well-understood. In the current study, differentially-expressed genes were scanned using an expression profile chip in New Zealand white rabbits (introduced breed) and Fujian yellow rabbits (local breed), and some of the genes were tested using reverse transcription-polymerase chain reaction. The amplification results were consistent with the microarray data. Fourteen and 13 genes involved in muscle development were identified in the dorsal longissimus and leg muscles, respectively. Myh6, Myh7, Myh7b, Myo5b, Tnnc1, Tpm3, and Acta2 were scanned in the longissimus and leg muscles. Thus, these genes may be involved in muscle fiber formation and muscle development in rabbits. This study provides a theoretical basis for improving meat quality, as well as for the future development and utilization of local meat rabbit breeds.