Novel ACTG1 mutation causing autosomal dominant non-syndromic hearing impairment in a Chinese family

γ -actin （ACTG1） gene is a cytoplasmic nonmuscle actin gene, which encodes a major cytoskeletal protein in the sensory hair cells of the cochlea. Mutations in ACTG1 were found to cause autosomal dominant, progressive, sensorineural hearing loss linked to the DFNA 20/26 locus on chromosome 17q25.3 in European and American families, respectively. In this study, a novel missense mutation （c.364A〉G; p.I122V） co-segregated with the affected individuals in the family and did not exist in the unaffected family members and 150 unrelated normal controls. The alteration of residue Ile122 was predicted to damage its interaction with actin-binding proteins, which may cause disruption of hair cell organization and function. These findings strongly suggested that the I122V mutation in ACTG1 caused autosomal dominant non-syndromic hearing impairment in a Chinese family and expanded the spectrum of ACTG1 mutations causing hearing loss.

Identification and Molecular Characterization of a Phytoplasma Associated with Pomegranate Fasciation Disease

To confirm phytoplasma infection,samples of pomegranate(Punica granatum L.)plants showing symptoms of fasciation were collected from an orchard located in Tai’an,Shandong Province,China.A fragment of approximately 1.2 kb was amplified with universal primers targeting the phytoplasma 16S r RNA gene from symptomatic pomegranate plants,while no fragment was obtained from healthy plants.The phytoplasma associated with the disease was designated as pomegranate fasciation(Po F).Two representative phytoplasma 16S r DNA gene sequences(Po F-Ch01 and Po F-Ch02)had 100%nucleotide sequence identity.The 16S r DNA sequence of Po F-Ch01 and Po F-Ch02 showed the highest similarity(99.6%)to that of‘P.granatum’phytoplasma isolate AY-PG,which belong to 16Sr I-B.Further phylogenetic analysis showed that Po F-Ch01 and Po F-Ch02 belonged to a cluster of 16Sr I subgroup members.In silico RFLP analysis indicated that Po F-Ch01 shared the highest similarity coefficient of 0.97 with reference strains of 16Sr I-B,M and N.Actual RFLP analysis of both enzymes Bst U I and Bfa I confirmed that of the virtual RFLP analysis.Combining these results,we concluded that Po F was a member of the‘Candidatus Phytoplasma asteris’group(16Sr I),and has very close relationship with 16Sr I-B subgroup.