Novel rhino-like SHJH^(hr) mice with thyroid dysfunction

A new Hairless(Hr)gene mutant mouse line(SHJH^(hr))was identified,which showed hairless skin in adult individuals as reported in rhino mice.Through Hr gene mutant identification with polymerase chain reaction(PCR)amplification and sequencing,seven mutants were identified,including nonsense mutant site 2134C→T(R467X),which produced a truncated Hr protein.Metabolic activity and heart rate were measured using a metabolic cage and blood pressure instrument,respectively.The SHJH^(hr) mice showed a strong metabolic rate,high heart rate,and low blood pressure.Histological analysis of the thyroid gland of SHJH^(hr) mice showed abnormal follicular structure and hypertrophic thyrocytes.Compared to ICR mice,thyroid function in 4-month-old SHJH^(hr) mice showed lower thyroid stimulating hormone(TSH)levels,and in 9-month-old SHJH^(hr) mice showed significantly higher TSH and thyroid hormone levels.These data indicate that SHJH^(hr) mice may be in a hyperthyroid state with increasing age.Thus,based on the above results,we successfully established a novel mouse model with thyroid dysfunction.

Biological and biochemical characterization of a red-eye mutant in Nilaparvata lugens （Hemiptera： Delphacidae）

A red-eye colony was established in our laboratory in brown planthopper （BPH）, Nilaparvata lugens （Stal）, a major rice pest in Asia. Except for the red-eye phenotype, no other differences were observed between the wild-type （brown eye） and the mutant-type （red eye） in external characters. Genetic analysis revealed that the red-eye phenotype was controlled by a single autosomal recessive allele. Biological studies found that egg produc- tion and egg viability in the red-eye mutant colony were not significantly different from those in the wild-type BPH. Biochemical analysis and electronic microscopy examination revealed that the red-eye mutants contained decreased levels of both xanthommatin （brown） and pteridine （red） and reduced number of pigment granules. Thus, the changes of amount and ratio of the two pigments is the biochemical basis of this red-eye mutation. Our results indicate that the red-eye mutant gene （red） might be involved in one common gene locus shared by the two pigments in pigment transportation, pigment granule formation or some other processes.

karmoisin and cardinal ortholog genes participate in the ommochrome synthesis of Nilaparvata lugens (Hemiptera:Delphacidae)

Ommochrome is the major source for eye coloration of all insect species so far examined.Phenoxazinone synthetase (PHS)has always been regarded as the terminal step enzyme for ommochrome formation,which is encoded by cardinal or karmoisin genes. Our previous study indicated that the karmoisin ortholog gene (Nl-karmoisin)product in the brown planthopper (BPH)was a monocarboxylate transporter,while not a PHS. Here,based on full-length complementary DNA,the cardinal ortholog gene in BPH (Nl-cardinal)product was predicted to be a haem peroxidase rather than a PHS.We suggest for the first time that neither karmoisin nor cardinal encodes the PHS,but whether PHS participates in BPH eye pigmentation needs further research.Nymphal RNA interference (RNAi)experiments showed that knockdown Nl-cardinal transcript led the BPH ocelli and compound eye to color change from brown to red,while knockdown Nl-karmoisin only made the ocelli present the red phenotype.Notably,not only the Nl-cardinal transcript, dscd injection (Nl-cardinal targeting double-stranded DNA (dsRNA))also significantly reduced the Nl-karmoisin transcript by 33.7%,while dska (Nl-karmoisin targeting dsRNA) injection did not significantly change the Nl-cardinal transcript.Considering the above RNAi and quantitative real-time polymerase chain reaction results,we propose that Nl-cardinal plays a more important role in ommochrome synthesis than Nl-karmoisin,and it may be an upstream gene of Nl-karmoisin.The present study suggested that both karmoisin and cardinal ortholog genes play a role in ommochrome synthesis in a hemimetabolous insect.