[Zinc finger E-box-binding homeobox 2 inhibits hepatitis B virus replication and expression].

Objective: To investigate the effect of zinc finger E-box-binding homeobox 2 (ZEB2) on hepatitis B virus (HBV) replication and expression. Methods: HepG2, HepG2.2.15, and HepAD38 cells were cultured separately, and Western blot was used to measure the expression of ZEB2. HepG2.2.15 cells were cultured and transfected with ZEB2 expression plasmids or shRNA targeting ZEB2. Western blot was used to measure the expression of ZEB2 and HBV core proteins, quantitative real-time PCR was used to measure HBV 3.5 kb RNA and HBV DNA, Southern blot was used to measure HBV replicative intermediate, and ELISA was used to measure the expression of HBsAg and HBeAg, in order to clarify the effect of ZEB2 on HBV replication and expression. The dual-luciferase reporter system was used to analyze the effect of ZEB2 on HBV promoter, and the chromatin immunoprecipitation assay was used to detect the binding of ZEB2 to HBV promoter. The t-test was used for comparison of means between groups. Results: The expression of ZEB2 was inhibited in the cells with HBV replication. Overexpression of ZEB2 reduced the level of HBV replication and expression by about 50% (P< 0.05). After ZEB2 was downregulated by shZEB2-1 or shZEB2-2, the level of HBV replicative intermediate increased from 58.53 ± 3.43 to 112.80 ± 5.03, and 128.30 ± 2.31, the relative expression level of HBV 3.5 kb RNA increased from 1.00 ± 0.01 to 2.03 ± 0.02 and 2.32 ± 0.03, the level of HBsAg increased from 35.63% ± 1.57% to 81.87% ± 0.43% and 100.00% ± 2.18%, and HBeAg increased from 37.00% ± 0.70% to 88.00% ± 2.60% and 100.00% ± 0.75%. Furthermore, ZEB2 could bind to HBV core promoter and inhibit its transcriptional activity. Conclusion: ZEB2 inhibits HBV replication and expression through binding to HBV core promoter and inhibiting its transcriptional activity.

Dlx1&2-dependent expression of Zfhx1b (Sip1, Zeb2) regulates the fate switch between cortical and striatal interneurons.

Mammalian pallial (cortical and hippocampal) and striatal interneurons are both generated in the embryonic subpallium, including the medial ganglionic eminence (MGE). Herein we demonstrate that the Zfhx1b (Sip1, Zeb2) zinc finger homeobox gene is required in the MGE, directly downstream of Dlx1&2, to generate cortical interneurons that express Cxcr7, MafB, and cMaf. In its absence, Nkx2-1 expression is not repressed, and cells that ordinarily would become cortical interneurons appear to transform toward a subtype of GABAergic striatal interneurons. These results show that Zfhx1b is required to generate cortical interneurons, and suggest a mechanism for the epilepsy observed in humans with Zfhx1b mutations (Mowat-Wilson syndrome).

Intrahepatic biliary anomalies in a patient with Mowat-Wilson syndrome uncover a role for the zinc finger homeobox gene zfhx1b in vertebrate biliary development.

BACKGROUND: zfhz1b is the causative gene for Mowat-Wilson syndrome, in which patients demonstrate developmental delay and Hirschsprung disease, as well as other anomalies. MATERIALS AND METHODS: We identified a patient with Mowat-Wilson syndrome who also developed cholestasis and histopathologic features consistent with biliary atresia, suggesting that mutations involving zfhz1b may lead to biliary developmental anomalies or injury to the biliary tract. We used the zebrafish model system to determine whether zfhx1b has a role in vertebrate biliary development. RESULTS: Using zebrafish we determined that zfhx1b was expressed in the developing liver during biliary growth and remodeling, and that morpholino antisense oligonucleotide-mediated knockdown of zfhx1b led to defects in biliary development. These findings were associated with decreased expression of vhnf1, a transcription factor known to be important in biliary development in zebrafish and in mammals. CONCLUSIONS: Our studies underscore the importance of genetic contributions in the etiology of infantile hepatobiliary disorders, including biliary atresia.

Characterization of Mesenchyme Homeobox 2 (MEOX2) transcription factor binding to RING finger protein 10.

The molecular mechanisms by which Mesenchyme Homeobox 2 (Meox2) regulates the proliferation, differentiation and migration of vascular smooth muscle cells and cardiomyocytes are not known. The discovery of MEOX2 binding proteins will aid in understanding how MEOX2 functions as a regulator of these key cellular processes. To identify MEOX2 binding proteins, a yeast two-hybrid screen of a human heart cDNA library was performed using a deleted MEOX2 bait protein that does not contain the histidine/glutamine rich region (MEOX2deltaHQ). Eleven putative interacting proteins were identified including RING finger protein 10 (RNF10). In vitro pull-down assays and co-immunoprecipitation studies in mammalian cells further supported the yeast data demonstrating RNF10 bound to MEOX2. The minimal RNF10 binding region of MEOX2 was determined to be a central region between the histidine/glutamine rich domain and the homeodomain (amino acids 101-185). The amino terminal region of RNF10, containing the RING finger domain, was not essential for the binding to MEOX2. Our results also demonstrated that MEOX2 activation of the p21WAF1 promoter was enhanced by RNF10 co-expression.

The genetic background of craniosynostosis syndromes.

Craniosynostosis syndromes are developmental disorders that cause an abnormal shape of the skull due to the premature fusion of cranial sutures. Enormous progress has been made recently in understanding the genetic background of these disorders and a classification of syndromes on a genetic basis is beginning to emerge. Members of at least three gene families that play an important role in vertebrate development are associated with different craniosynostosis syndromes. Here we review the genetic aspects of this fast-moving field.