[From random mutagenesis to precise genome editing: the development and evolution of genome editing techniques in Drosophila].

Drosophila melanogaster, an important model organism for studying life science, has contributed more to the research of genetics, developmental biology and biomedicine with the development of genome editing techniques. Drosophila genome-editing techniques have evolved from random mutagenesis to precise genome editing and from simple mutant construction to diverse genome editing methods since the 20th century. Chemical mutagenesis, using Ethyl methanesulfonate (EMS), is an important technique to study gene function in forward genetics, however, the precise knockout of Drosophila genes could not be achieved. The gene targeting technology, based on homologous recombination, has accomplished the precise editing of Drosophila genome for the first time, but with low efficiency. The CRISPR/Cas9 (Clustered regularly interspaced short palindromic repeats/CRISPR-associated protein)-mediated precise genome editing is simple, fast and highly efficient compared with the gene targeting technology in Drosophila. In this review, we focus on Drosophila gene knockout, and summarize the evolution of genome editing techniques in Drosophila, emphasizing the development and applications of gene targeting, zinc-finger nuclease (ZFN), transcription activator-like effector nuclease (TALEN) and CRISPR/Cas9 techniques.

[CT and pathological manifestations of intraductal papillary mucinous neoplasm of pancreas: a comparative study].

OBJECTIVE: To evaluate the diagnostic value of CT in pancreas intraductal papillary mucinous neoplasm (IPMN) by analyzing its CT feature and pathological findings. METHODS: The clinical and CT data was analyzed among 39 patients with IPMN whose diagnosis was confirmed by pathology. The CT manifestations were classified into 3 types: simple main pancreatic duct enlargement; main pancreatic duct enlargement combined with pancreatic cystic lesion; and simple pancreatic cystic lesion. The correlation between the CT types and Takada pathological types (main duct type, branch type, and mixed type) was analyzed. All the cases were pathologically classified into benign and malignant/boundary groups. Statistical tests of the difference of CT features (mural nodule, septa, size, caliber of main pancreatic duct and common bile duct) between the 2 groups were performed. RESULTS: The CT type I matched the main duct type, the CT type II mainly matched the branch type and mixed type, and the CT type III matched the branch type (P < 0.001). The probability of benign lesion was 92% with no mural nodule in the lesion, while the probability of benign lesion was only 42% with mural nodule presented (P = 0.003). In terms of the septa, there was no significant difference between benign and malignant lesions (P = 0.793). The size of malignant/boundary lesions exceeded that of benign lesions (P = 0.016). There were no significant difference in calibers of main pancreatic duct and common bile duct between the benign and malignant/ boundary groups. Without considering pathological grouping the caliber of main pancreatic duct exceeded that of the common bile duct in all the cases (P = 0.02). CONCLUSION: CT typing of IPMN well matches the pathological typing which benefits the CT diagnosis of IPMN. The caliber of main pancreatic duct usually exceeds that of common bile duct in IPMN. This feature contributes to its diagnosis.