Analysis of microRNA expression profiles during the differentiation of chicken embryonic stem cells into male germ cells.

The differentiation of embryonic stem cells (ESCs) into germ cells in vitro could have very promising applications for infertility treatment and could provide an excellent model for uncovering the molecular mechanisms of germline generation. This study aimed to investigate the differentially expressed miRNAs (DEMs) during the differentiation of chicken ESCs (cESCs) into male germ cells and to establish a profile of the DEMs. Cells before and after induction were subjected to miRNA sequencing (miRNA-seq). A total of 113 DEMs were obtained, including 61 upregulated and 52 downregulated DEMs. GO and KEGG enrichment analyses showed that the target genes were enriched mainly in the MAPK signaling pathway, HTLV infection signaling pathway, cell adhesion molecule (CAM)-related pathways, viral myocarditis, Wnt signaling pathway, ABC transporters, TGF-ß signaling pathways, Notch signaling pathways and insulin signaling pathway. The target genes of the miRNAs were related to cell binding, cell parts and biological regulatory processes. Six DEMs, let-7k-5p, miR-132c-5p, miR-193a-5p, miR-202-5p, miR-383-5p and miR-6553-3p, were assessed by qRT-PCR, and the results were consistent with the results of miRNA-seq. Based on qRT-PCR and western blot verification, miR-383-5p and its putative target gene STRN3 were selected to construct an STRN3 3'-UTR dual-luciferase gene reporter vector and its mutant vector. The double luciferase reporter activity of the cotransfected STRN3-WT + miR-383-5p mimics group was significantly lower (by approximately 46%) than that of the other five groups (p < 0.01). There was no significant difference in luciferase activity among the other 5 groups. This study establishes a DEM profile during the process of cESC differentiation into male germ cells; illustrates the mechanisms by which miRNAs regulate target genes; provides a theoretical basis for further research on the mechanisms of the formation and regulation of male germ cells; and provides an important strategy for gene editing, animal genetic resource protection and transgenic animal production.

Isolation, characterization and differentiation of dermal papilla cells from Small-tail Han sheep.

Dermal papilla cells (DPCs) are the key dermal component of the hair follicle that directly regulates hair follicle development, growth and regeneration. Successfully isolated and cultured DPCs from Small-tail Han sheep could provide a good model for the study of hair follicle development mechanism in vitro. DPCs were isolated using enzyme digestion and dissecting microscope from Small-tail Han sheep. Adherent cells were identified by cell characteristics, particular gene expression, differentiation capability to adipocyte and osteoblast using specific differentiation mediums. Additionally, flow cytometry was used to detect the cell cycle of DPCs. Cells originating from the dermal papilla showed the morphological appearance of mesenchymal cells (fibroblast-like cells). Purified DPCs were positive for α-SMA (α smooth muscle actin) and vimentin; in addition to their strong proliferation abilities in vitro, these DPCs can be differentiated into adipocyte and osteoblasts lineage under appropriate culture condition. DPCs were successfully isolated and subcultured from Small-tail Han sheep, which exhibited progenitor cell features and multiple differentiation potency. It provides a material for studying the molecular mechanism of hair follicle development and hair cycle, which will promote wool production in the future.

Transcript variants of long-chain acyl-CoA synthase 1 have distinct roles in sheep lipid metabolism.

Mutton has recently been identified to be a consumer favorite, and intermuscular fat is the key factor in determining meat tenderness. Long-chain acyl-CoA synthetase 1 (ACSL1) is a vital subtype of the ACSL family that is involved in the synthesis of lipids from acyl-CoA and the oxidation of fatty acids. The amplification of the ACSL1 gene using rapid amplification of cDNA ends revealed that the alternative polyadenylation (APA) results in two transcripts of the ACSL1 gene. Exon 18 had premature termination, resulting in a shorter CDS region. In this study, the existence of two transcripts of varying lengths translated normally and designated ACSL1-a and ACSL1-b was confirmed. Overexpression of ACSL1-a can promote the synthesis of an intracellular diglyceride, while ACSL1-b can promote triglyceride synthesis. The transfection of ACSL1 shRNA knocks down both the transcripts, the triglyceride content was significantly reduced after differentiation and induction; and lipidome sequencing results exhibited a significant decrease in 14-22 carbon triglyceride metabolites. The results of the present study indicated that the ACSL1 gene played a crucial role in the synthesis of triglycerides. Furthermore, the two transcripts involved in various interactions in the triglyceride synthesis process may be the topic of interest for future research and provide a more theoretical basis for sheep breeding.

Integrated analysis of expression profiles with meat quality traits in cattle.

MicroRNAs (miRNAs) play a vital role in improving meat quality by binding to messenger RNAs (mRNAs). We performed an integrated analysis of miRNA and mRNA expression profiling between bulls and steers based on the differences in meat quality traits. Fat and fatty acids are the major phenotypic indices of meat quality traits to estimate between-group variance. In the present study, 90 differentially expressed mRNAs (DEGs) and 18 differentially expressed miRNAs (DEMs) were identified. Eighty-three potential DEG targets and 18 DEMs were used to structure a negative interaction network, and 75 matching target genes were shown in this network. Twenty-six target genes were designated as intersection genes, screened from 18 DEMs, and overlapped with the DEGs. Seventeen of these genes enriched to 19 terms involved in lipid metabolism. Subsequently, 13 DEGs and nine DEMs were validated using quantitative real-time PCR, and seven critical genes were selected to explore the influence of fat and fatty acids through hub genes and predict functional association. A dual-luciferase reporter and Western blot assays confirmed a predicted miRNA target (bta-miR-409a and PLIN5). These findings provide substantial evidence for molecular genetic controls and interaction among genes in cattle.

Identification of Hub Genes of Keloid Fibroblasts by Coexpression Network Analysis and Degree Algorithm.

BACKGROUND: Keloid is a benign dermal tumor characterized by abnormal proliferation and invasion of fibroblasts. The establishment of biomarkers is essential for the diagnosis and treatment of keloids. METHODS: We systematically identified coexpression modules using the weighted gene coexpression network analysis method (WGCNA). Differential expressed genes (DEGs) in GSE145725 and genes in significant modules were integrated to identify overlapping key genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were then performed, as well as protein-protein interaction (PPI) network construction for hub gene screening. RESULTS: Using the R package of WGCNA, 22 coexpression modules consisting of different genes were identified from the top 5,000 genes with maximum mean absolute deviation in 19 human fibroblast samples. Blue-green and yellow modules were identified as the most important modules, where genes overlapping with DEGs were identified as key genes. We identified the most critical functions and pathways as extracellular structure organization, vascular smooth muscle contraction, and the cGMP-PKG signaling pathway. Hub genes from key genes as BMP4, MSX1, HAND2, TBX2, SIX1, IRX1, EDN1, DLX5, MEF2C, and DLX2 were identified. CONCLUSION: The blue-green and yellow modules may play an important role in the pathogenesis of keloid. 10 hub genes were identified as potential biomarkers and therapeutic targets for keloid.

LINC01123 potentially correlates with radioresistance in glioma through the miR-151a/CENPB axis.

Radiotherapy represents the most effective nonsurgical therapy, whereas acquired radioresistance remains a major challenge in glioma treatment. Deregulation of long noncoding RNAs (lncRNAs) is frequently involved in tumorigenesis. This study investigates the role of LINC01123 in radioresistance in glioma with molecules involved. LINC01123 was identified as the most upregulated gene in a glioma gene expression dataset GSE103227. LINC01123 was highly expressed in the radioresistant glioma tissues radioresistant glioma U251 (U251R) cells. Downregulation of LINC01123 reduced cell proliferation and colony formation abilities, as well as resistance to apoptosis of the U251R cells after 4 Gy X-ray irradiation. The micro(mi)RNA-151a gene (miR-151a) was a poorly expressed miRNA in glioma, and it was a target of LINC01123. The centromere protein B gene (CENPB) mRNA was a direct target of miR-151a and demonstrated a positive correlation with LINC01123 in glioma tissues and cells. Further inhibition of miR-151a or overexpression of CENPB restored radioresistance of glioma cells. In addition, silencing of LINC01123 suppressed growth of xenograft tumors formed by U251R cells in nude mice. To conclude, the present study demonstrates that LINC01123 serves as a sponge for miR-151a and upregulates CENPB expression to increase the radioresistance of glioma cells in vitro and in vivo.

Exosomal microRNA-19b targets FBXW7 to promote colorectal cancer stem cell stemness and induce resistance to radiotherapy.

Colorectal cancer (CRC) continues to be one of the most malignant cancers with a high mortality rate to date. Promoting the radio-responsiveness of CRC is of great importance for local control and prognosis. In this study, we examined the roles of exosomal microRNA-19b (miR-19b) in CRC radioresistance. The regulatory role of miR-19b in CRC stem cells and radiotherapy-resistant cells was determined using miRNA microarray analysis, and its prognostic value was probed using the TCGA database. It was found that miR-19b was overexpressed in CRC tissues, which indicated a poor prognosis. CRC-derived exosomes (EXOs) enhanced the radio-resistance and stemness properties of CRC cells via delivery of miR-19b in vitro and in vivo. FBXW7 was identified as a putative target of miR-19b. On the contrary, reintroduction of FBXW7 reversed the effects of miR-19b on radioresistance and stemness properties. Furthermore, the Wnt/ß-catenin pathway activity was elevated in CRC cells upon EXOs treatment, decreased after miR-19b downregulation, and increased again after FBXW7 downregulation. These results suggest that miR-19b inhibition could enhance the efficacy of radiotherapy while reducing the stemness properties, thus presenting a promising strategy for sensitizing CRC cells to radiotherapy.

Effect of the ACAA1 Gene on Preadipocyte Differentiation in Sheep.

Acetyl-CoA acyltransferase 1 (ACAA1) functions as a key regulator of fatty acid ß-oxidation in peroxisomes by catalyzing the cleavage of 3-ketoacyl-CoA to acetyl-CoA and acyl-CoA, which participate in the extension and degradation of fatty acids. Thus, ACAA1 is an important regulator of lipid metabolism and plays an essential role in fatty acid oxidation and lipid metabolism. Our previous study findings revealed that ACAA1 is closely associated with the peroxisome proliferator-activated receptor (PPAR) signaling and fatty acid metabolism pathways, which are involved in fat deposition in sheep, leading to our hypothesis that ACAA1 may be involved in fat deposition by regulating lipid metabolism. However, the associated molecular mechanism remains unclear. In the present study, to assess the potential function of ACAA1 in sheep preadipocyte differentiation, we knocked down and overexpressed ACAA1 in sheep preadipocytes and evaluated the pattern of ACAA1 gene expression during preadipocyte differentiation by qRT-PCR. ACAA1 was significantly expressed in the early stage of adipocyte differentiation, and then its expression decreased. ACAA1 deficiency increased lipid accumulation and the triglyceride content and promoted sheep preadipocyte differentiation, whereas ACAA1 overexpression inhibited adipogenesis and decreased lipid accumulation and the triglyceride content. Simultaneously, we demonstrated that ACAA1 deficiency upregulated the expressions of the adipogenic marker genes PPARγ and C/EBPα in sheep preadipocytes, but ACAA1 overexpression inhibited the expressions of these markers, indicating that ACAA1 affects lipid metabolism by regulating adipogenic marker genes. Our results may promote a better understanding of the regulation of adipogenesis by ACAA1.

IGFBP7 downregulation or overexpression effect on bovine preadipocyte differentiation.

The insulin-like growth factor binding-protein 7 (IGFBP7) has binding affinities to IGFs and is able to either positively or negatively regulate the IGFs signaling pathway. It also plays a crucial role in cell growth, differentiation and development in an IGF-independent manner. Herein, we investigated the specific regulation of the gene encoding for IGFBP7during the differentiation process of the adipocyte cells of the Yan Yellow Cattle by interfering with or by overexpressing the IGFBP7 gene. As a result, we found that the mRNA expression levels of IGFBP7 were significantly increased during the formation of progenitor cells. In addition, the expression levels of the lipoprotein lipase (LPL) and transcription factors (PPARγ, C/EBPα) were also significantly increased. IGFBP7 gene overexpression and RNA interfering promoted and inhibited respectively the lipid accumulation and triglyceride production in mature adipocytes, and the expression of the LPL and transcription factors (PPARγ, C/EBPα). The changes in the protein expression levels of IGFBP7 and adipogenic factors were in accord with the changes observed in the mRNA levels. In conclusion, our results indicate that IGFBP7 plays an important regulatory role in the differentiation of preadipocyte cells.

ALDH1A1 effect on Yan Yellow Cattle preadipocyte differentiation.

Aldehyde dehydrogenase 1A1 (ALDH1A1) is a cytosolic enzyme that mainly catalyzes the oxidation of acetaldehyde into acetic acid and participates in the regulation of differentiation and gene expression in fat cell growth and development. However, the physiological role of ALDH1A1 in the formation of fat cell precursors in the Yan Yellow Cattle is still not clear. Herein, we investigated the specific regulation of the gene encoding for ALDH1A1 during the differentiation process of the adipocyte cells of the Yan Yellow Cattle by interfering or overexpressing the ALDH1A1 gene. As a result, we found that the mRNA expression levels of ALDH1A1 were significantly increased during the formation of progenitor cells. In addition, the expression levels of the Lipoprotein lipase (LPL) and transcription factors (PPARγ, C/EBPα) were also significantly increased. ALDH1A1 gene overexpression and RNA interfering promoted and inhibited respectively the lipid accumulation and triglyceride production in mature adipocytes, and the expression of the LPL and transcription factors (PPARγ, C/EBPα). The changes in the protein expression levels of ALDH1A1 and adipogenic factors were in accord with the changes observed in the mRNA levels. In conclusion, our results indicate that ALDH1A1 plays an important regulatory role in the differentiation of preadipocyte cells.

Effects of Long-Chain Fatty Acyl-CoA Synthetase 1 on Diglyceride Synthesis and Arachidonic Acid Metabolism in Sheep Adipocytes.

Long-chain fatty acyl-CoA synthetase (ACSLs) is an essential enzyme for the synthesis of fatty acyl-CoA. ACSL1 plays a key role in the synthesis of triglycerides, phospholipids, and cholesterol esters. BACKGROUND: In the current study, triglyceride content did not increase after overexpression of the ACSL1 gene. METHODS: RNA-seq and lipid metabolome profiling were performed to determine why triglyceride levels did not change with ACSL1 overexpression. RESULTS: Fatty acyl-CoA produced by ACSL1 was determined to be involved in the diglyceride synthesis pathway, and diglyceride content significantly increased when ACSL1 was overexpressed. Moreover, the arachidonic acid (AA) content in sheep adipocytes significantly increased, and the level of cyclooxygenase 2 (COX2) expression, the downstream metabolic gene, was significantly downregulated. Knocking down the ACSL1 gene was associated with an increase in COX2 mRNA expression, as well as an increase in prostaglandin content, which is the downstream metabolite of AA. CONCLUSIONS: The overexpression of the ACSL1 gene promotes the production of AA via downregulation of COX2 gene expression.

Effects of puerarin on the AKT signaling pathway in bovine preadipocyte differentiation.

OBJECTIVE: Puerarin has the potential of regulating the differentiation of preadipocytes, but its mechanism of action has not yet been elucidated. Adipocytes found in adipose tissue, the main endocrine organ, are the main sites of lipid deposition, and are widely used as a cell model in the study of in vitro fat deposition. This study aimed to investigate the effects of puerarin on adipogenesis in vitro. METHODS: Puerarin was added to the culture medium during the process of adipogenesis. The proliferation and differentiation of bovine preadipocytes was measured through cell viability and staining with Oil Red O. The content of triacylglycerol (TG) was measured using a triglyceride assay kit. The mRNA and protein expression levels of adipogenic genes, peroxisome proliferator-activated receptor-γ (PPARγ) and CCAAT/enhancer-binding protein-α (C/EBPα), were measured using quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting, respectively. RESULTS: The addition of puerarin significantly increased adipogenesis of bovine preadipocytes and enhanced the mRNA and protein level expression of PPARγ (p&lt;0.01). The expression of P-Akt increased after adipogenic hormonal induction, whereas puerarin significantly increased PPARγ expression by promoting the Akt signaling component, P-Akt. The mechanism of adipogenesis was found to be related to the phosphorylation level of Ser473, which may activate the downstream signaling of the Akt pathway. CONCLUSION: Puerarin was able to promote the differentiation of preadipocytes and improve fat deposition in cattle. The mechanism of adipogenesis was found to be related to the phosphorylation level of Ser473.

A study on changes and clinical significance of blood glucose, blood lipid and inflammation in patients with ovarian cancer.

PURPOSE: To investigate the changes in blood glucose, blood lipid and inflammation in patients with ovarian cancer and their clinical significance. METHODS: 67 patients diagnosed with ovarian cancer and treated in our hospital from January 2018 to December 2018 constituted the observation group. Fifty healthy women in the corresponding time period were enrolled as the control group. The levels of blood glucose, blood lipid and inflammation were compared between the two groups, and then the changes in those levels in ovarian cancer patients in different clinical stages were analyzed. RESULTS: The levels of fasting blood glucose and 2-h postprandial blood glucose of the observation group were significantly higher than those of the control group, and they were also significantly higher in patients in stage III-IV than those in stage I-II (p<0.05). In the observation group, the levels of total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C) were lower than those in the control group. Compared with the patients in stage I-II, the patients in stage III-IV had remarkably lower levels of TC and HDL-C (p<0.05). The levels of C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) in the observation group were evidently higher than those in the control group, and they were markedly higher in patients in stage III-IV than those in stage I-II (p<0.05). CONCLUSIONS: Both the metabolism disorders of blood lipid and blood glucose and inflammatory response are more obvious in ovarian cancer patients, indicating that these indicators have a place for early screening and clinical treatment of ovarian cancer.

RNA-Seq Analysis Reveals a Positive Role of HTR2A in Adipogenesis in Yan Yellow Cattle.

In this study, we performed high throughput RNA sequencing at the primary bovine preadipocyte (Day-0), mid-differentiation (Day-4), and differentiated adipocyte (Day-9) stages in order to characterize the transcriptional events regulating differentiation and function. The preadipocytes were isolated from subcutaneous fetal bovine adipose tissues and were differentiated into mature adipocytes. The adipogenic characteristics of the adipocytes were detected during various stages of adipogenesis (Day-0, Day-4, and Day-9). We used RNA sequencing (RNA-seq) to investigate a comprehensive transcriptome information of adipocytic differentiation. Compared to the pre-differentiation stage (Day-0), 2510 genes were identified as differentially expressed genes (DEGs) at the mid-differentiation stage (Day-4). We found 2446 DEGs in the mature adipocytic stage relative to the mid-differentiation stage. Some adipogenesis-related transcription factors, CCAAT-enhancer-binding protein α (C/EBPα) and peroxisome proliferator-activated receptor γ (PPARγ) were differentially expressed at Day-0, Day-4, and Day-9. We further investigated the adipogenic function of 5-hydroxytryptamine receptor 2A (HTR2A) in adipogenesis. Overexpression of HTR2A stimulated the differentiation of preadipocytes, and knockdown of HTR2A had opposite effects. Furthermore, functional enrichment analysis of DEGs revealed that the PI3K-Akt signaling pathway was the significantly enriched pathway, and HTR2A regulated adipogenesis by activating or inhibiting phosphorylation of phospho-AKT (Ser473). In summary, the present study provides the first comparative transcription of various periods of adipocytes in cattle, which presents a solid foundation for further study into the molecular mechanism of fat deposition and the improvement of beef quality in cattle.

A comparison of transcriptomic patterns measured in the skin of Chinese fine and coarse wool sheep breeds.

We characterised wool traits, and skin gene expression profiles of fine wool Super Merino (SM) and coarse wool Small Tail Han (STH) sheep. SM sheep had a significantly higher total density of wool follicles, heavier fleeces, finer fibre diameter, and increased crimp frequency, staple length and wool grease (lanolin) production. We found 435 genes were expressed at significantly different levels in the skin of the two breeds (127 genes more highly in SM and 308 genes more highly in STH sheep). Classification of the genes more highly expressed in SM sheep revealed numerous lipid metabolic genes as well as genes encoding keratins, keratin-associated proteins, and wool follicle stem cell markers. In contrast, mammalian epidermal development complex genes and other genes associated with skin cornification and muscle function were more highly expressed in STH sheep. Genes identified in this study may be further evaluated for inclusion in breeding programs, or as targets for therapeutic or genetic interventions, aimed at altering wool quality or yield. Expression of the lipid metabolic genes in the skin of sheep may be used as a novel trait with the potential to alter the content or properties of lanolin or the fleece.

Comparative analysis on genome-wide DNA methylation in longissimus dorsi muscle between Small Tailed Han and Dorper×Small Tailed Han crossbred sheep.

OBJECTIVE: The objective of this study was to compare the DNA methylation profile in the longissimus dorsi muscle between Small Tailed Han and Dorper×Small Tailed Han crossbred sheep which were known to exhibit significant difference in meat-production. METHODS: Six samples (three in each group) were subjected to the methylated DNA immunoprecipitation sequencing (MeDIP-seq) and subsequent bioinformatics analyses to detect differentially methylated regions (DMRs) between the two groups. RESULTS: 23.08 Gb clean data from six samples were generated and 808 DMRs were identified in gene body or their neighboring up/downstream regions. Compared with Small Tailed Han sheep, we observed a tendency toward a global loss of DNA methylation in these DMRs in the crossbred group. Gene ontology enrichment analysis found several gene sets which were hypo-methylated in gene-body region, including nucleoside binding, motor activity, phospholipid binding and cell junction. Numerous genes were found to be differentially methylated between the two groups with several genes significantly differentially methylated, including transforming growth factor beta 3 (TGFB3), acyl-CoA synthetase long chain family member 1 (ACSL1), ryanodine receptor 1 (RYR1), acyl-CoA oxidase 2 (ACOX2), peroxisome proliferator activated receptor-gamma2 (PPARG2), netrin 1 (NTN1), ras and rab interactor 2 (RIN2), microtubule associated protein RP/EB family member 1 (MAPRE1), ADAM metallopeptidase with thrombospondin type 1 motif 2 (ADAMTS2), myomesin 1 (MYOM1), zinc finger, DHHC type containing 13 (ZDHHC13), and SH3 and PX domains 2B (SH3PXD2B). The real-time quantitative polymerase chain reaction validation showed that the 12 genes are differentially expressed between the two groups. CONCLUSION: In the current study, a tendency to a global loss of DNA methylation in these DMRs in the crossbred group was found. Twelve genes, TGFB3, ACSL1, RYR1, ACOX2, PPARG2, NTN1, RIN2, MAPRE1, ADAMTS2, MYOM1, ZDHHC13, and SH3PXD2B, were found to be differentially methylated between the two groups by gene ontology enrichment analysis. There are differences in the expression of 12 genes, of which ACSL1, RIN2, and ADAMTS2 have a negative correlation with methylation levels and the data suggest that DNA methylation levels in DMRs of the 3 genes may have an influence on the expression. These results will serve as a valuable resource for DNA methylation investigations on screening candidate genes which might be related to meat production in sheep.

Molecular cloning of the HGD gene and association of SNPs with meat quality traits in Chinese red cattle.

Homogentisate 1, 2 dioxygenase (HGD) is one of six enzymes required for the catabolism of the aromatic amino acids phenylalanine and tyrosine. Here we present the nucleotide sequence of transcripts of the bovine HGD gene. The full length cDNA of bovine HGD has been identified, encoding a deduced protein of 445 amino acids (Accession No. FJ515744). The bovine HGD gene comprises 14 exons and 13 introns. This is the first published cDNA bovine sequences that share high sequence similarity with other species. Semi-quantitative RT-PCR analysis demonstrated that the bovine HGD transcript was mainly expressed in liver and kidney tissues. Nine single nucleotide polymorphisms (SNPs) were identified, five in the coding region and four intronic. Four of the SNPs change an amino acid in the HGD protein sequence. Genotype and allelic frequencies were determined in Chinese red cattle breeds. Ten haplotypes were determined based upon the genotype of 9 SNPs. Moreover, for the first time an association was reported between HGD gene polymorphism and meat quality traits in Chinese red cattle (n = 224). Marker-trait association analyses showed that the HGD/PvuII genotypes showed a significant effect on meat cooking rate, muscle fiber diameter, and shear force (P < 0.05). The HGD DraIII genotypes showed a significant effect on muscle fiber diameter, shear force, and drip loss (P < 0.05). The HGD/AluI genotypes showed a significant effect on meat cooking rate, shear force, and drip loss (P < 0.05). The HGD/DraI genotypes showed a significant effect on meat cooking rate and shear force (P < 0.05). The HGD/EcoRV genotypes showed a significant effect on meat cooking rate, muscle fiber diameter, and shear force (P < 0.05). In all loci, no statistically significant differences were observed for pHu (P > 0.05). This is the first incidence where polymorphisms of a bovine HGD gene have demonstrated a correlation with meat traits in Chinese red cattle.

[Estrogen receptor as a candidate gene for prolificacy of small tail Han sheep].

Single nucleotide polymorphism in exon 1 of the estrogen receptor (ESR) gene was detected by PCR-SSCP in both high fecundity sheep breeds (Small Tail Han sheep, Hu sheep and German Mutton Merino sheep) and low fecundity sheep breeds (Dorset sheep,Suffolk sheep). Results indicated that there were three genotypes (AA, AB and BB) in all three high fecundity sheep breeds, but only two genotypes (AA, AB) in both low fecundity breeds. In Hu sheep,German Mutton Merino sheep, Small Tail Han sheep, Suffolk sheep and Dorset sheep,the frequency of allele A was 0.672, 0.786, 0.846, 0.857 and 0.867, respectively, and the frequency of allele B was 0.328, 0.214, 0.154, 0.143, and 0.133, respectively. Sequencing revealed a C-->G mutation at 363 bp of exon 1 of ESR gene in the BB genotype in comparison to the AA genotype. The genotype distribution was significantly different between Small Tail Han sheep and Hu sheep (P<0.01) and between Dorset sheep and Hu sheep (P <0.05). There was no difference in genotype distribution between other sheep breeds. The Small Tail Han sheep ewes with genotypes AB or BB had 0.51 (P < 0.05) and 0.7 (P < 0.05) more lambs than those with genotype AA, respectively. These results showed that the estrogen receptor locus is either a major gene that influences the prolificacy in Small Tail Han sheep or in close linkage with such a gene. In view of our results, marker-assisted selection using ESR is warranted to increase litter size in sheep and will be of considerable economic value to mutton producers.

[Study on relationships between seven microsatellite loci and somatic cell score in Beijing Holstein cows].

Genetic variation of seven microsatellite loci BM1818, BM1258, BM1443, BM1905, BM302, BM4505 and CYP21 which were closely linked to somatic cell score (SCS) was analyzed in 240 Beijing Holstein cows with nondenaturing polyacrylamide gel electrophoresis. Allele frequencies, heterozygosity, polymorphic information content, the effective number of alleles of seven microsatellite loci were calculated. Relationships between seven microsatellite loci and somatic cell score in Beijing Holstein cows were primarily analyzed by least squares linear model. Least squares means of SCS for BM1818 (284 bp/284 bp), BM1258 (106 bp/92 bp), BM1443 (166 bp/160 bp), BM1905 (187 bp/187 bp), BM302 (142 bp/140 bp), BM4505 (240 bp/236 bp) and CYP21 (215 bp/198 bp) were relatively lower,and their genotypes were the most favorable genotypes in respective locus for mastitis resistance. Least squares means of SCS for BM1818 (286 bp/286 bp), BM1258 (102 bp/102 bp), BM1443 (170 bp/160 bp), BM1905 (197 bp/195 bp), BM302 (154 bp/145 bp), BM4505 (240 bp/238 bp) and CYP21 (204 bp/192 bp) were relatively higher,and their genotypes were the most unfavorable genotypes in respective locus for mastitis resistance. The information found in the present study would be very important for improving mastitis resistance in dairy cattle by marker assisted selection.