Porcine skeletal muscle development regulated by MicroRNA: a review / 生物工程学报

The growth and development of skeletal muscle is an important factor affecting pork production and quality, which is elaborately regulated by many genetic and nutritional factors. MicroRNA (miRNA) is a non-coding RNA with a length of about 22 nt, which binds to the 3'UTR sequence of the mRNA of the target genes, and consequently regulates its post-transcriptional expression level. In recent years, a large number of studies have shown that miRNAs are involved in various life processes such as growth and development, reproduction, and diseases. The role of miRNAs in the regulation of porcine skeletal muscle development was reviewed, with the hope to provide a reference for the genetic improvement of pigs.

Transcriptome profiling reveals differential expression of genes potentially involved in muscle and adipose tissue development of cattle

BACKGROUND: To identify differentially expressed genes (DEGs) between muscle and adipose in cattle, we analyzed the data from the RNA sequencing of three Angus×Qinchuan crossbred cattle. RESULTS: Searched the Gene Expression Omnibus (GEO) for a microarray dataset of Yan yellow cattle, GSE49992. After the DEGs were identified, we used STRING and Cytoscape to construct a protein­protein interaction (PPI) network, subsequently analyzing the major modules of key genes. In total, 340 DEGs were discovered, including 21 hub genes, which were mainly enriched in muscle contraction, skeletal muscle contraction, troponin complex, lipid particle, Z disc, tropomyosin binding, and actin filament binding. CONCLUSIONS: In summary, these genes can be regarded as candidate biomarkers for the regulation of muscle and adipose development.

Rearrangements of nitrogen fixation (nif) genes in the heterocystous cyanobacteria.

In the vegetative cells of heterocystous cyanobacteria, such as Anabaena, two Operons harbouring the nitrogen fixation (nif) genes contain two separate intervening DNA elements resulting in the dispersion of genes and impaired gene expression. A 11 kb element disrupts the nifD gene in the nifH, D-K operon. It contains a 11 bp sequence (GGATTACTCCG) directly repeated at its ends and harbours a gene, xisA, which encodes a site-specific recombinase. A large 55 kb element interrupts the fdxN gene in the nifB fdxN-nifS-nifU operon. It contains two 5 bp direct repeats (TATTC) at its ends and accommodates at least one gene, xisF, which encodes another site-specific recombinase. During heterocyst differentiation both the discontinuities are precisely excised by two distinct site-specific recombination events. One of them is brought about by the XisA protein between the 11 bp direct repeats. The second one is caused by the XisF protein and occurs between the 5 bp direct repeats. As a consequence the 11kb and 55 kb elements are removed from the chromosome as circles and functional nif Operons are created. Nitrogenase proteins are then expressed from the rearranged genes in heterocysts and aerobic nitrogen fixation ensues. How these elements intruded the nif genes and how and why are they maintained in heterocystous cyanobacteria are exciting puzzles engaging considerable research effort currently. The unique developmental regulation of these gene rearrangements in heterocystous cyanobacteria is discussed.