FHL3 promotes the formation of fast glycolytic muscle fibers by interacting with YY1 and muscle glycolytic metabolism.

The proportions of the various muscle fiber types are important in the regulation of skeletal muscle metabolism, as well as animal meat production. Four-and-a-half LIM domain protein 3 (FHL3) is highly expressed in fast glycolytic muscle fibers and differentially regulates the expression of myosin heavy chain (MyHC) isoforms at the cellular level. Whether FHL3 regulates the transformation of muscle fiber types in vivo and the regulatory mechanism is unclear. In this study, muscle-specific FHL3 transgenic mice were generated by random integration, and lentivirus-mediated gene knockdown or overexpression in muscles of mice or pigs was conducted. Functional analysis showed that overexpression of FHL3 in muscles significantly increased the proportion of fast-twitch myofibers and muscle mass but decreased muscle succinate dehydrogenase (SDH) activity and whole-body oxygen consumption. Lentivirus-mediated FHL3 knockdown in muscles significantly decreased muscle mass and the proportion of fast-twitch myofibers. Mechanistically, FHL3 directly interacted with the Yin yang 1 (YY1) DNA-binding domain, repressed the binding of YY1 to the fast glycolytic MyHC2b gene regulatory region, and thereby promoted MyHC2b expression. FHL3 also competed with EZH2 to bind the repression domain of YY1 and reduced H3K27me3 enrichment in the MyHC2b regulatory region. Moreover, FHL3 overexpression reduced glucose tolerance by affecting muscle glycolytic metabolism, and its mRNA expression in muscle was positively associated with hemoglobin A1c (HbA1c) in patients with type 2 diabetes. Therefore, FHL3 is a novel potential target gene for the treatment of muscle metabolism-related diseases and improvement of animal meat production.

Breeding and study of two new photoperiod- and thermo-sensitive genic male sterile lines of polyploid rice (Oryza sativa L.).

Male sterile lines play an important role in the utilization of heterosis. To explore and exploit the heterosis of polyploid hybrid rice, two photoperiod- and thermo-sensitive genic male sterile lines of polyploid rice, PS006 and PS012, were bred via chromosome doubling, complex hybridization and self-breeding. The characteristics of these two lines, including the agronomic traits, growth, development, fertility transformation and combining ability, were investigated. Both lines had good agronomic characteristics and flowering habits, a high outcrossing rate, obvious fertility alterations and good combining abilities. Their hybrids showed strong heterosis and great potential for increasing rice productivity and quality. The new polyploid rice photoperiod- and thermo-sensitive genic male sterile lines will provide material for further research into polyploidy and hybrid vigour in rice and promote the exploitation of polyploid hybrid rice.

Chemical Constituents of the Aerial Parts of Euphorbia nematocypha.

Chemical constituents of the dried aerial parts of Euphorbia nematocypha were investigated. A new oleanane triterpenoid, trans, trans-2',4'- hexadienedioicacid-1'-ß-amyrin ester (1), together with, ß-amyrin (2), ß-amyrin acetate (3), betulinic acid (4), ellagic acid (5), oleanolic acid (6), ß-sitosterol (7), kaempferol (8), quercetin (9), lupeol (10) and pseudo-taraxasterol (11) were isolated from the methylene chloride extract. Their structures were elucidated on the basis of extensive spectroscopic (1D- & 2D-NMR) and ESI-MS analysis and comparison with data reported in the literature. The new isolated triterpenoid showed moderate cytotoxic activities against HeLa and MCF-7cell lines.