Synthesis of bifunctional molecules containing [12]aneN3 and coumarin moieties as effective DNA condensation agents and new non-viral gene vectors.

A series of bifunctional molecules with different combinations of macrocyclic polyamine [12]aneN3 and coumarin moieties, 4a/b and 5a/b, were synthesized by a two-step copper(I)-mediated alkyne­azide click reactions between 1,3,5-tris(azidomethyl)benzene and Boc-protected N-propynyl-[12]aneN3/7-propynyloxycoumarins. Agarose gel electrophoresis experiments indicated that bifunctional molecules 4b and 5b effectively induced complete plasmid DNA condensation at concentrations up to 40 µM. It was found that the structural variation had a major impact on the condensation behavior of these compounds. The electrostatic interaction involving the [12]aneN3 moiety can be compensated by the binding contribution of the coumarin units during the DNA condensation process. These two types of interaction showed different effects on the reversibility of DNA condensation. Results from studies using dynamic laser scattering, atomic force microscopy, and EB replacement assay further supported the above conclusion. Cytotoxicity assays on bifunctional compounds 4a/b and 5a/b indicated their low cytotoxicity. Results from cellular uptake and cell transfection experiments proved that bifunctional compounds 4b and 5b successfully served as non-viral gene vectors. Furthermore, methyl substituents attached to the coumarin unit (4b and 5b) greatly enhanced their DNA condensation capability and gene transfection. These bifunctional molecules, with the advantages of lower cytotoxicity, good water solubility, and potential structural modification, will have great potential for the development of new non-viral gene delivery agents.

Apoptosis induced by one new podophyllotoxin glucoside in human carcinoma cells.

4-Demethyl-picropodophyllotoxin 7'-O-beta-D-glucopyranoside (4DPG), a new podophyllotoxin glucoside, was isolated from the rhizomes of Sinopodophyllum emodi (Wall.) Ying and showed cytotoxic effects in human carcinoma cells. Among the target cells (HeLa, A2 and SH-SY5Y), the cytotoxic effects of 4DPG showed dose- and time-dependency. Furthermore, the cervical carcinoma cell line, HeLa, was more sensitive to 4DPG. Flow cytometric analysis demonstrated the presence of apoptotic cells with low DNA content, a decrease of cell population at the G1 phase, and a concomitant increase of cell population at the G2/M phase. 4DPG also caused DNA fragmentation in HeLa cells. Treatment with 0.1 microM 4DPG increased p53 expression and Bax/Bcl-2 ratio in HeLa cells, as well as in A2 cells. These results suggested that 4DPG-induced apoptosis might be through a p53-dependent pathway.

[Molecular cloning and expression analysis of a novel human gene ZNF18].

The zinc-finger motif found in many transcription factors is thought to be important for human heart development and diseases. This study reports cloning and expression analysis of a novel human zinc finger protein ZNF18 cDNA. The ZNF18 cDNA is 2,767 bp in length encoding a 549-amino-acid protein that contains a SCAN-box, a KRAB box and five consecutive C2H2 zinc finger motifs. ZNF18 shows high similarity with mouse Zfp535 (identity 77%). The ZNF18 gene is located on human chromosome 17p12-p13 with 9 exons and 8 introns. ZNF18 was ubiquitously expressed in adult mouse tissues except heart as revealed by Northern blot. Whole-mount in situ hybridization showed that expression of ZNF18 in mouse embryos was very dynamic. Expression was predominantly in extraembryonic tissues of E7.5 mouse embryo. By E8.5, ZNF18 began to express in anterior of trunk, and became abundant in tail and heart at E9.0, especially in the embryo heart at E10.5. These expression results suggest that ZNF18 may play an important role in the development of embryo heart.

Review: Epigenetic regulation of adipocyte differentiation and adipogenesis.

It is generally agreed that adipocytes originate from mesenchymal stem cells in what can be divided into two processes: determination and differentiation. In the past decade, many factors associated with epigenetic signals have been proved to be pivotal for the appropriate timing of adipogenesis progression. A large number of coregulators at critical gene promoters set up specific patterns of DNA methylation, histone acetylation and methylation, and nucleosome rearrangement, that act as an epigenetic code to modulate the correct progress of adipocyte differentiation and adipogenesis during adipogenesis. In this review, we focus on the functions and roles of epigenetic processes in preadipocyte differentiation and adipogenesis.

[Screening of proteins interacting with Dishevelled2 in mouse 11.5dpc embryo library].

Dishevelled proteins are multifunctional and highly conserved. These proteins are also required for the specification of cell fate and polarity by secreted Wnt proteins. To investigate the molecular mechanism of Dishevelled in mediating Wnt signal transduction, a mouse 11.5dpc embryo library was screened by yeast-two-hybrid system to find mouse Dishevelled2 DEP domain and C-terminal interacting proteins. 15 possitive clones were identified from 4.1 x 10(6) transformants. The DNA sequences of the positive AD/library plasmids were determined. The BLAST results revealed that one of the positive clones contained N-terminus cDNA fragments (amino acids 6-122) of Gli3 protein. The interaction between Dv12 and Gli3 detected by yeast two-hybrid system suggests that Gli3 might play a role in some biological processes with Dishevelled.