Wuying Chu

Phylogenetic studies of three sinipercid fishes (Perciformes: Sinipercidae) based on complete mitochondrial DNA sequences

The sinipercids are a group of 12 species of freshwater percoid fish endemic to East Asia and their phylogenetic placements have perplexed generations of taxonomists. We cloned and sequenced the complete mitochondrial DNA (mtDNA) of three sinipercid fishes (Siniperca chuatsi, S. kneri, and S. scherzeri) to characterize and compare their mitochondrial genomes. The mitochondrial genomes of S. chuatsi, S. kneri, and S. scherzeri were 16,496, 17,002, and 16,585 bp in length, respectively. The organization of the three mitochondrial genomes is similar to those reported from other fish mitochondrial genomes, which contains 37 genes (13 protein-coding genes, 2 ribosomal RNAs, and 22 transfer RNAs) and a major non-coding control region. Among the 13 protein-coding genes of all the three sinipercid fishes, three reading-frame overlaps were found on the same strand. There is an 81-bp tandem repeat cluster at the end of CSB-3 in the S. scherzeri control region. The complete mitochondrial genomes of the three sinipercids should be useful for the evolutionary studies of sinipercids and other vertebrate species.

Smyd1b is required for skeletal and cardiac muscle function in zebrafish

Myofibrillogenesis is critical for muscle cell differentiation and contraction. This study shows that Smyd1b plays a key role in myofibrillogenesis in muscle cells. Knockdown of smyd1b results in up-regulation of hsp90α1 and unc45b gene expression, increased myosin degradation, and disruption of sarcomere organization in zebrafish embryos.

Smyd1b_tv1, a Key Regulator of Sarcomere Assembly, Is Localized on the M-Line of Skeletal Muscle Fibers

Background Smyd1b is a member of the Smyd family that plays a key role in sarcomere assembly during myofibrillogenesis. Smyd1b encodes two alternatively spliced isoforms, smyd1b_tv1 and smyd1b_tv2, that are expressed in skeletal and cardiac muscles and play a vital role in myofibrillogenesis in skeletal muscles of zebrafish embryos. Methodology/Principal Findings To better understand Smyd1b function in myofibrillogenesis, we analyzed the subcellular localization of Smyd1b_tv1 and Smyd1b_tv2 in transgenic zebrafish expressing a myc-tagged Smyd1b_tv1 or Smyd1b_tv2. The results showed a dynamic change of their subcellular localization during muscle cell differentiation. Smyd1b_tv1 and Smyd1b_tv2 were primarily localized in the cytosol of myoblasts and myotubes at early stage zebrafish embryos. However, in mature myofibers, Smyd1b_tv1, and to a small degree of Smyd1b_tv2, exhibited a sarcomeric localization. Double staining with sarcomeric markers revealed that Smyd1b_tv1was localized on the M-lines. The sarcomeric localization was confirmed in zebrafish embryos expressing the Smyd1b_tv1-GFP or Smyd1b_tv2-GFP fusion proteins. Compared with Smyd1b_tv1, Smyd1b_tv2, however, showed a weak sarcomeric localization. Smyd1b_tv1 differs from Smyd1b_tv2 by a 13 amino acid insertion encoded by exon 5, suggesting that some residues within the 13 aa insertion may be critical for the strong sarcomeric localization of Smyd1b_tv1. Sequence comparison with Smyd1b_tv1 orthologs from other vertebrates revealed several highly conserved residues (Phe223, His224 and Gln226) and two potential phosphorylation sites (Thr221 and Ser225) within the 13 aa insertion. To determine whether these residues are involved in the increased sarcomeric localization of Smyd1b_tv1, we mutated these residues into alanine. Substitution of Phe223 or Ser225 with alanine significantly reduced the sarcomeric localization of Smyd1b_tv1. In contrast, other substitutions had no effect. Moreover, replacing Ser225 with threonine (S225T) retained the strong sarcomeric localization of Smyd1b_tv1. Conclusion/Significance Together, these data indicate that Phe223 and Ser225 are required for the M-line localization of Smyd1b_tv1.

Analysis of the variable sites and phylogenetic studies of complete mitochondrial DNA based on the Siniperca scherzeri (Perciformes: Sinipercidae) from four different areas

In this study, we cloned and sequenced the complete mitochondrial DNAs of Chinese mandarin fish, Siniperca scherzeri populations from four different areas of the Yangtze River and the Pearl River systems in China. In the Yangtze River system, fish samples were taken from three regions, Dongting Lake (DT), Poyang Lake (PL) and Xiangjiang River (XR). In the Pearl River system, fish samples were collected from the Lijiang River (LR). The sizes of their complete mitochondrial genome were 16,502 bp (LR), 16,508 bp (PL), 16,502 bp (XR) and 16,508 bp (DT), respectively. The organization of the S. scherzeri mitochondrial genomes was similar to those reported from other fish mitochondrial genomes. Phylogenetic analyses using N–J computational algorithms showed that the Sinipercidaes are monophyletic and can be divided into two genera, Siniperca and Coreoperca. The S. scherzeri could be divided into two groups along the Yangtze River system and the Pearl River.

Transcriptome Analysis and Postprandial Expression of Amino Acid Transporter Genes in the Fast Muscles and Gut of Chinese Perch (Siniperca chuatsi).

The characterization of the expression and regulation of growth-related genes in the muscles of Chinese perch is of great interest to aquaculturists because of the commercial value of the species. The transcriptome annotation of the skeletal muscles is a crucial step in muscle growth-related gene analysis. In this study, we generated 52 504 230 reads of mRNA sequence data from the fast muscles of the Chinese perch by using Solexa/Illumina RNA-seq. Twenty-one amino acid transporter genes were annotated by searching protein and gene ontology databases, and postprandial changes in their transcript abundance were assayed after administering a single satiating meal to Chinese perch juveniles (body mass, approximately 100 g), following fasting for 1 week. The gut content of the Chinese perch increased significantly after 1 h and remained high for 6 h following the meal and emptied within 48–96 h. Expression of eight amino acid transporter genes was assayed in the fast muscles through quantitative real-time polymerase chain reaction at 0, 1, 3, 6, 12, 24, 48, and 96 h. Among the genes, five transporter transcripts were markedly up-regulated within 1 h of refeeding, indicating that they may be potential candidate genes involved in the rapid-response signaling system regulating fish myotomal muscle growth. These genes display coordinated regulation favoring the resumption of myogenesis responding to feeding.

Complete mitochondrial genome of the hybrid of Ctenopharyngodon idellus (♀) × Elopichthys bambusa (♂).

Abstract In this study, we determined the complete mitochondrial DNA sequence of the hybrid of Ctenopharyngodon idellus (♀) × Elopichthys bambusa (♂). The total length of the mitochondrial genome was 16,609 bp (accession number KM401549), with the base composition of 31.89% A, 26.33% C, 15.68% G, 26.11% T. The genome contained 2 ribosomal RNA genes, 13 protein-coding genes, 22 transfer RNA genes, and a major non-coding control region (D-loop region). Except for ND6 and 8 tRNAs, all other genes were encoded on the heavy strand. The arrangements of these genes were similar to that found in the other teleosts. The complete mitogenome may provide important date set for the study of genetic mechanism in the hybrid fish of Cyprinidae.

The phylogenetic placement of Siniperca obscura base on complete mitochondrial DNA sequence

Abstract The extant freshwater sinipercids represent a group of 12 species and they are endemic to East Asia. In this study, we cloned and sequenced the complete mitochondrial DNA of Siniperca obscura from the Lijiang River. The size of the complete mitochondrial genome is 16,492 bp. The organization of the mitochondrial contained 37 genes (13 protein-coding genes, 2 ribosomal RNA and 22 transfer RNAs) and a major non-coding control region as well as those reported sinipercid fishes. Among the 13 protein-coding genes, three reading-frame overlaps were found: ATP8 and ATP6 overlap by 10 nucleotides and ND4 and ND4L overlap by 7 nucleotides and ND5 and ND6 overlap by 5 nucleotides. Phylogenetic analyses using N-J and maximum parsimony (MP) computational algorithms showed that S. chuatsi and S. kneri are sister species, next joined by S. Obscura, based on combined 12 protein-coding genes (excluding DN6).

The complete mitochondrial genome sequence of Cirrhinus mrigala (♀) × Labeo rohita (♂)

Abstract We cloned and sequenced the complete mitochondrial DNA (mtDNA) of Cirrhinus mrigala (♀) × Labeo rohita (♂) by PCR-based method. The total of the mtDNA was 16,595 bp. It consisted of 13 protein-coding genes, 22 tRNAs, 2 rRNA genes, and one putative control region (D-loop region). The overall base composition on strand was as follows A: 32.09%, G: 15.51%, C: 27.95%, T: 24.45%, and the A + T content 56.54%. All the protein-coding genes initiated by typical ATG codon, and ten genes ended with the complete stop codon TAA or TAG, while COII2, ND4 and Cytb genes terminated with GCC, TAT and GCT. The control region contains a thiolases active site, EGF-like domain signature and two anaphylatoxin domain signature. This mitogenome sequence data would play an important role in population genetics and phylogenetics of the hybrid fish in the Cyprinidae family.