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In flowering plants, meiocytes develop from subepidermal cells in anthers and ovules. The mechanisms that integrate gene-regulatory processes with meiotic programs during reproductive development remain poorly characterized. Here, we show that Arabidopsis thaliana plants deficient in ACTIN-RELATED PROTEIN6 (ARP6), a subunit of the SWR1 ATP-dependent chromatin-remodeling complex, exhibit defects in prophase I of female meiosis. We found that this meiotic defect is likely due to dysregulated expression of meiotic genes, particularly those involved in meiotic recombination, including DMC1 (DISRUPTED MEIOTIC cDNA1). Analysis of DMC1 expression in arp6 mutant plants indicated that ARP6 inhibits expression of DMC1 in the megasporocyte and surrounding nonsporogeneous ovule cells before meiosis. After cells enter meiosis, however, ARP6 activates DMC1 expression specifically in the megasporocyte even as it continues to inhibit DMC1 expression in the nonsporogenous ovule cells. We further show that deposition of the histone variant H2A.Z, mediated by the SWR1 chromatin-remodeling complex at the DMC1 gene body, requires ARP6. Therefore, ARP6 regulates female meiosis by determining the spatial and temporal patterns of gene expression required for proper meiosis during ovule development. [ABSTRACT FROM AUTHOR]

Deposition of the histone variant H2A.Z at gene bodies regulates transcription by modifying chromatin accessibility in plants. However, the role of H2A.Z enrichment at the promoter and enhancer regions is unclear, and how H2A.Z interacts with other mechanisms of chromatin modification to regulate gene expression remains obscure. Here, we mapped genome-wide H2A.Z, H3K4me3, H3K27me3, Pol II, and nucleosome occupancy in Arabidopsis inflorescence. We showed that H2A.Z preferentially associated with H3K4me3 at promoters, while it was found with H3K27me3 at enhancers, and that H2A.Z deposition negatively correlated with gene expression. In addition, we demonstrated that H2A.Z represses gene expression by establishing low gene accessibility at +1 nucleosome and maintaining high gene accessibility at −1 nucleosome. We further showed that the high measures of gene responsiveness correlate with the H2A.Z-associated closed +1 nucleosome structure. Moreover, we found that H2A.Z represses enhancer activity by promoting H3K27me3 and preventing H3K4me3 histone modifications. This study provides a framework for future studies of H2A.Z functions and opens up new aspects for decoding the interplay between chromatin modification and histone variants in transcriptional control. [ABSTRACT FROM AUTHOR]

Muscle fiber is the basic unit of skeletal muscle. Muscle fiber types play a crucial role in improving meat quality. In the current study, Wistar rats were chronic injected with 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) for four weeks in order to define the 5′-AMP-activated protein kinase (AMPK) protein activity on muscle fiber composition, enzyme activity and the mRNA expression of muscle fiber type-related genes in gastrocnemius (GS) muscle. Food intake and body weight did not show a significant difference after AICAR treatment (P >.05). The AICAR treatment caused a significantly increased number and area proportion of type I muscle fiber and expression level MyHC I mRNA (P <.05), succinic dehydrogenase (SDH) and malate dehydrogenase (MDH) activities (P <.05), but decrease in the number proportion of type IIB muscle fiber and MyHC IIb and MyHC IIx mRNA level (P <.05). The Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) mRNA level (P <.05) was increased and glucose transporter 4 (GLUT-4) mRNA level tended to be higher (P =.052) in the AICAR group. These results demonstrated that chronic AICRA treatment induces oxidative muscle fiber switching, enhances oxidative enzyme activity and GLUT4 mRNA level, mediated by PGC-1α. [ABSTRACT FROM AUTHOR]

The effects of two feeding regimens on meat quality, myosin heavy chain (MyHC) types, and key factors regulating muscle fiber type (AMP‐activated protein kinase [AMPK] and peroxisome proliferator‐activated receptor‐coactivator‐1α [PGC‐1α]) in the biceps femoris muscle of Mongolia sheep were investigated. A total of 20 Mongolia sheep were weaning for 90 days and divided into two groups (pasture group (P) and confinement group (C)) at 10.36 ± 0.35 kg of weaning weight. After weaning, sheep were pasture fed or confinement fed for 9 months. The results showed that live weights, carcass weight, intramuscular fat (IMF), and Warner–Bratzler shear force (WBSF) in P group were significantly lower (p <.05) than that in C group. Compared with P group, color evaluations with respect to L* and b* values were significantly higher (p <.05) in C group. Expression of the MyHC I gene in the P group was significantly higher, while MyHC IIa and MyHC IIb genes expression was significantly lower (p <.05) than that in C group. Also, AMPK activity and expression of AMPKα2 and PGC‐1α genes were significantly higher (p <.05) in P group compared with C group. The present study indicated that muscle fiber composition was one of the key differences leading to the differences of meat quality in different feeding regimens. AMPK, particularly AMPKα2, and PGC‐1α were considered to be two key factors regulating muscle fiber types in Mongolia sheep. The results support that AMPK activity and the expression of AMPKα2 and PGC‐1α genes may affect the composition of muscle fibers; thus, AMPK activity and the expression of AMPKα2 and PGC‐1α genes had an effect on meat quality by changed composition of muscle fibers. [ABSTRACT FROM AUTHOR]

With the tremendous success of the artificial breeding of Hexagrammos otakii , the yield has been substantially improved. However, intensive farming often results in bacterial diseases; hence it is imperative to find new antimicrobial molecules. In the present study, we identified a homologous cDNA fragment of collectin-10 from H. otakii , designated as HoCL-10. The cDNA length is 899 bp, which contains an open reading frame (ORF) of 816 bp encoding a secreted protein with 272 amino acid residues. The peptide of HoCL-10 contains an N-terminal collagen domain, a neck region, and a C-terminal carbohydrate recognition domain. The qRT-PCR results revealed that HoCL-10 mRNA was highest expressed in the liver and skin and was significantly induced post-LPS stimulation. The sugar and bacteria binding assay suggested that the recombinant HoCL-10 (rHoCL-10) could recognize various pathogen-associated molecular patterns (PAMPs) and bacteria. For effect on cells, rHoCL-10 enhanced the phagocytosis and migration ability of the macrophage indicated using pro-phagocytosis assay and trans -well assay. To determine the role of HoCL-10 in the complement system, the interaction between HoCL-10 and mannose-binding lectin associated serine protease 1, 2 (MASP-1, 2) were analyzed and demonstrated using ELISA and Far-western. And in vivo , the concentration of membrane-attack complex (MAC) in fish plasma was significantly down-regulated post-injection with HoCL-10 antibody. Finally, the bacteria challenge experiment was performed, implying that HoCL-10 may assist the host in defending against microbial invasion. The findings suggest that HoCL-10 may play crucial roles in host defense against microorganisms, possibly through opsonizing pathogens and activating the complement system. • A collectin-10 gene from Hexagrammos otakii (HoCL-10) was identified. • HoCL-10 mRNAs were up-regulated in the liver and skin post LPS stimulation. • The recombination protein of HoCL-10 (rHoCL-10) recognized PAMPs and microbials. • rHoCL-10 may function in the complement activation process and anti-infections. [ABSTRACT FROM AUTHOR]

Highlights • Feeding regimens effected gene expression of FADS1 and FADS2 in adipose tissue. • The content of n-3 PUFA, especially EPA and DHA is higher in pastured sheep. • Different tissues have variable sensibilities to feeding regimens. Abstract The present study investigated the effects of two feeding regimens on meat quality, fatty acid profile and metabolism as it relates to gene expression in Sunit sheep. Two feeding regimens were used (pasture feeding and barn feeding, PF and BF) each containing 10 Sunit sheep. Results of this study indicated that PF sheep had significantly (P < 0.05) higher L* and b* values in their muscle compared to BF sheep. Also, the fatty acid composition of longissimus dorsi muscle and subcutaneous adipose tissues differed between feeding regimens. In this respect, concentrations of palmitic acid (C16:0) in the subcutaneous adipose tissue were significantly (P < 0.05) higher in BF sheep. Pastured sheep exhibited greater concentrations of polyunsaturated fatty acids (PUFA) including: linolenic acid (C18:3) (P < 0.001), DHA (P < 0.05), EPA (P < 0.001) and CLA cis-9, trans-11(P < 0.05) in their muscle compared to BF sheep. The expression of nine candidate genes related to fatty acid metabolism were analyzed by qPCR. In longissimus dorsi muscle, expression of acetyl CoA carboxylase (ACACA; P < 0.05) was up-regulated in BF sheep. Expression of the peroxisome proliferator activated receptor (PPARγ) (P < 0.05), stearoyl CoA desaturase (SCD) (P < 0.01), fatty acid desaturase1 (FADS1) (P < 0.05) and fatty acid desaturase 2 (FADS2) (P < 0.05) were up-regulated in PF sheep. Pasture feeding also increased (P < 0.05) expression of lipoprotein lipase (LPL), PPARγ, SCD, FADS1and fatty acid elongase 5 (Elove5) in the subcutaneous adipose tissue, however, the feeding regimens did not change expression of fatty acid synthase (FASN) and carnitine palmitoyl transferase I (CPT1). The results of this study indicated that the feeding regimen could be an important tool in manipulating the fatty acid profile of animal adipose tissue by altering the gene expression of enzymes involved in fat metabolism. [ABSTRACT FROM AUTHOR]

Proper flower development is essential for sexual reproductive success and the setting of fruits and seeds. The availability of a high quality genome sequence for pineapple makes it an excellent model for studying fruit and floral organ development. In this study, we sequenced 27 different pineapple floral samples and integrated nine published RNA-seq datasets to generate tissue- and stage-specific transcriptomic profiles. Pairwise comparisons and weighted gene co-expression network analysis successfully identified ovule-, stamen-, petal- and fruit-specific modules as well as hub genes involved in ovule, fruit and petal development. In situ hybridization confirmed the enriched expression of six genes in developing ovules and stamens. Mutant characterization and complementation analysis revealed the important role of the subtilase gene AcSBT1.8 in petal development. This work provides an important genomic resource for functional analysis of pineapple floral organ growth and fruit development and sheds light on molecular networks underlying pineapple reproductive organ growth. Wang et al. perform RNA-Seq on pineapple floral samples and also use previously published RNA-Seq datasets to generate tissue- and stage-specific transcriptomic profiles. The authors use weighted gene co-expression network analysis to identify gene networks, bringing insight to underlying pineapple reproductive organ growth. [ABSTRACT FROM AUTHOR]