A histone H3K27me3 reader cooperates with a family of PHD finger-containing proteins to regulate flowering time in Arabidopsis.

Trimethylated histone H3 lysine 27 (H3K27me3) is a repressive histone marker that regulates a variety of developmental processes, including those that determine flowering time. However, relatively little is known about the mechanism of how H3K27me3 is recognized to regulate transcription. Here, we identified BAH domain-containing transcriptional regulator 1 (BDT1) as an H3K27me3 reader. BDT1 is responsible for preventing flowering by suppressing the expression of flowering genes. Mutation of the H3K27me3 recognition sites in the BAH domain disrupted the binding of BDT1 to H3K27me3, leading to de-repression of H3K27me3-enriched flowering genes and an early-flowering phenotype. We also found that BDT1 interacts with a family of PHD finger-containing proteins, which we named PHD1-6, and with CPL2, a Pol II carboxyl terminal domain (CTD) phosphatase responsible for transcriptional repression. Pull-down assays showed that the PHD finger-containing proteins can enhance the binding of BDT1 to the H3K27me3 peptide. Mutations in all of the PHD genes caused increased expression of flowering genes and an early-flowering phenotype. This study suggests that the binding of BDT1 to the H3K27me3 peptide, which is enhanced by PHD proteins, is critical for preventing early flowering.

[A new triterpenic acid from the roots of Rosa laevigata].

This study was designed to investigate triterpenoids from the roots of Rosa laevigata Michx. The silica gel column chromatography was used to separate the chemical constituents from the roots of Rosa laevigata Michx. HPLC was used to analyze its purity and chemical constitution. Spectroscopy methods were used to determine their structures. Five constituents were isolated and identified as19α-OH-3ß-E-feruloyl corosolic acid (1), 23-hydroxy-tormentic acid (2), 2α, 3ß, 19α, 23- tetrahydroxy-12-en-28-oleanolic acid (3), 2α, 3α, 20ß- trihydroxyurs-13 (18)-en-28-oic-acid (4), 2α, 3ß, 20ß-trihydroxyurs-13 (18)-en-28-oic-acid (5). Compound 1 was assigned as a new compound, compounds 4, 5 were obtained from the genus Rosa for the first time.

[Bilateral facial nerve paralysis-diagnosis and treatment].

OBJECTIVE: To observe the ways of diagnosis and treatment of bilateral facial nerve palsy. METHODS: Seven cases of bilateral facial nerve paralysis in 1996 - 2003 were retrospectively reviewed, and then the ways of diagnosis and therapies of these cases were analyzed. There were 6 patients with doubtless diagnosis. They were diagnosed as acute leukaemia, Vogt-Koyanagi-Harada disease (VKH), Machado-Jesoph disease, bilateral mandible fractures, Guillain-Barré syndrome, and Bell's palsy. The last one was diagnosed as Herpes zoster virus infection or Lyme disease. In all these cases, there were 4 of 5 positive cerebrospinal fluids test, 1 of 6 positive lyme antibody test, 2 of 5 positive images test, 7 of 7 EMG and Br test showed that the paralysis was peripheral palsy. All the 7 cases were treated with steroid and vitamin. RESULTS: House-Brackmann I was defined as complete recovery, after up to 2 months follow up, there were four cases got completely recovery while 2 cases incomplete recovery, and 1 case was not reacted to the therapy. CONCLUSIONS: Bilateral facial nerve paralysis was rare, and it was difficult to diagnosis and differentiation, while diagnostic mistakes would be serious. More attention should be paid to it in clinic.

[The use of muscle autograft denatured by microwave for repair of gaps in removal of facial neuromas].

OBJECTIVE: To study the clinical value of muscle autograft denatured by microwave for repair of gaps in removal of facial neuromas. METHODS: Two cases of patients with facial nerve Schwann cell neuromas were reported. The operations for removal of facial neuromas were completed, and the gaps of the nerves were repaired with muscle autograft denatured by microwave of 250 W for 120 sec. RESULTS: The patients were followed up for two years, and the recovery of facial function on the affected sides were satisfactory. CONCLUSION: Muscle autograft denatured by microwave technique is convenient, highly efficient for repairing facial nerve gap after removal of facial neuroma.