Behavioral abnormalities observed in Zfhx2-deficient mice.

Zfhx2 (also known as zfh-5) encodes a transcription factor containing three homeobox domains and 18 Zn-finger motifs. We have reported that Zfhx2 mRNA is expressed mainly in differentiating neurons in the mouse brain and its expression level is negatively regulated by the antisense transcripts of Zfhx2. Although the expression profile of Zfhx2 suggests that ZFHX2 might have a role in a particular step of neuronal differentiation, the specific function of the gene has not been determined. We generated a Zfhx2-deficient mouse line and performed a comprehensive battery of behavioral tests to elucidate the function of ZFHX2. Homozygous Zfhx2-deficient mice showed several behavioral abnormalities, namely, hyperactivity, enhanced depression-like behaviors, and an aberrantly altered anxiety-like phenotype. These behavioral phenotypes suggest that ZFHX2 might play roles in controlling emotional aspects through the function of monoaminergic neurons where ZFHX2 is expressed. Moreover, considering their phenotypes, the Zfhx2-deficient mice may provide a novel model of human psychiatric disorders

An E. coli promoter that is sensitive to visible light

It has been discovered that expression of promoter activity can be inhibited by visible light when specific fragments of E. coli DNA are inserted in a vector system designed to assay for promoter activity. These fragments have been located on regions of the E. coli chromosome to which no gene has been assigned to date. The effective wavelength of light that produces this phenomenon has been determined

Enhanced depression-like behavior of <i>Zfhx2</i>-deficient mice.

<p>(A, B) Porsalt forced swim test: the percentage of time in immobile posture of the mutant mice was significantly higher (A) and the distance traveled by the mutant mice was significantly shorter (B) than those of the controls. (C) Tail suspension test: the percentage of time in immobile posture of the mutant mice was significantly higher than that of the control mice.</p

Structure and expression of mouse <i>Zfhx2</i>.

<p>(A) Structure of ZFHX2 and related proteins. ZFHX2 is a protein of 2562 amino acids containing 18 zinc fingers (green ovals) and three homeodomains (red squares). (B) <i>Zfhx2</i>, <i>Zfhx3</i>, and <i>Zfhx4</i> mRNA detected by semi-quantitative RT-PCR in various RNA sources. Note that cDNAs were amplified for 30 cycles for brains of different developmental stages, whereas for 35 cycles for various adult tissues. (C–E) Expression of <i>Zfhx2</i> (C), <i>Zfhx3</i> (D), and <i>Zfhx4</i> (E) mRNA in the parasagittal sections of an E15.5 mouse brain. These three genes were expressed in substantially similar patterns with the highest expression level of <i>Zfhx3</i>. (F, G) Expression of <i>Zfhx2</i> mRNA (F) and the ZFHX2 protein (G) was compared on adjacent coronal sections of an E15.5 brain. mRNA expressed in the thalamic region (Th) was translated, whereas mRNA expressed in the cerebral cortex (Cx) was not translated: this situation made the expression patterns of ZFHX2 and ZFHX3 more alike in the protein level than in the mRNA level. (H–J) Expression of <i>Zfhx2</i> (H), <i>Zfhx3</i> (I), and <i>Zfhx4</i> (J) mRNA in the coronal sections of an adult brain. Cerebral cortex (Cx), hippocampus (Hp), thalamus (Th), caudate putamen (CP). Expression levels of all three genes were decreased compared with those in the embryonic brain, but <i>Zfhx2</i> maintained higher level of expression than the others. (K–P) Expression of ZFHX2 protein in the adult brain. The pyramidal layer of hippocampus (K, Py), the suprachiasmatic nucleus (L, SCN), laterodorsal thalamic nucleus (M, LD), lateral geniculate nucleus (N, LGN), substantia nigra pars compacta (O, SNc), and magnocellular part of the red nucleus suprachiasmic (P, RMC). (Q–Y) Double-color in situ hybridization with <i>Zfhx2</i> and tyrosine hydroxylase (<i>Th</i>) probes. The <i>Zfhx2</i> mRNA (red) was highly expressed in the <i>Th</i> mRNA (green)-positive cells in the substantia nigra pars compacta (SNc). <i>Zfhx2</i> mRNA was coexpressed with <i>Th</i> mRNA also in the ventral tegmental area (VTA) at a slightly lower level.</p

Locomotor activity measured in open field test.

<p>Distance traveled (A, B), stereotypic behavior (C), vertical activity (D), and time spent in the center area (E). Measurements are blocked in 5 min (A, C, D, and E) or in 1 min (B, shown only for the first 10 min). The <i>Zfhx2</i>-deficient mice were generally hyperactive but were hypoactive in the initial period in the open field.</p

Spatial reference memory.

<p>Barnes maze test was performed to assess spatial reference memory. There was no significant difference in latency (A) and number of errors (B) to reach the target hole during the training period. (C) Probe trial conducted 1 day after the last training session. The results were analyzed using two-way ANOVA followed by Fisher’s PLSD post hoc test. A significant difference was found in the effect of (genotype) × (hole position ( = distance from target)) interaction (<i>F</i>_11,418 = 2.989, <i>p</i> = 0.0008), although the difference of the time spent around the target did not reach a statistically significant level (genotype effect, <i>F</i>_1,38 = 4.003, <i>p</i> = 0.0526).</p

List of behavioral tests.

*<p>; Age (weeks old) of the youngest animals of the group at the start of the test. The oldest animals are 3 weeks (1st group) or 4 weeks (2nd group) older than the age indicated.</p>**<p>; Sections in the text where the results are described. Subsections of Results are; 2, General characteristics of <i>Zfhx2</i>-deficient mice; 3, Locomotor activity and anxiety-like behavior; 4, Depression-like behavior; 5, Sensorimotor gating; 6, Spatial reference memory; 7, Other behavioral tests.</p