ZNF232: structure and expression analysis of a novel human C(2)H(2) zinc finger gene, member of the SCAN/LeR domain subfamily

Identification and characterization of two novel human SCAN domain-containing zinc finger genes ZNF396 and ZNF397

We have identified two novel human SCAN domain genes ZNF396 and ZNF397, which are clustered within the region of chromosome 18q12. Three isoforms of ZNF396 transcript, 1.5, 2.5 and 3.9-kb, are expressed highly in liver. Four isoforms of ZNF397 transcript, 1.7, 2.5, 7.0 and 9.0-kb, are expressed in a variety of tissues, with varying levels. The SCAN-(C(2)H(2))(X) genes encode two distinct proteins due to a unique alternative splicing mechanism. Both ZNF396-fu (full zinc fingers) and ZNF397-fu consist of a SCAN domain in the N-terminal region and many consecutive C(2)H(2) zinc finger repeats in the C-terminal region. ZNF396-nf (no zinc fingers) and ZNF397-nf encode 210 and 198 amino acids, respectively, containing the SCAN domain only. ZNF396-fu, ZNF396-nf, ZNF397-fu or ZNF397-nf can homo-associate, while ZNF396-fu hetero-associates with ZNF396-nf, and ZNF397-fu hetero-associates with ZNF397-nf. ZNF396-nf and ZNF397-nf polypeptides are expressed diffusely in the cells, while ZNF396-fu and ZNF397-fu polypeptides target specifically to the nuclei. ZNF396-fu, ZNF396-nf and ZNF397-nf can repress reporter gene transcription, with ZNF397-nf having the strongest repression activity. Deletion analysis revealed that ZNF397-fu is a transcriptional activator without its nine zinc finger repeats.

A candidate region for Asperger syndrome defined by two 17p breakpoints

Asperger syndrome (AS) is a mild form of autistic disorder characterised by impairment in social interaction as well as a restricted pattern of behaviour, interests, and activities. Two patients with AS and balanced translocations t(13;17) and t(17;19), respectively, were identified. Fluorescent in situ hybridisation (FISH) analysis with chromosome 17 specific clones to metaphase chromosomes from both patients showed that the chromosome 17 breakpoints are located within a 300 kb region at 17p13. The region spans 14 known genes. The expression of these genes was analysed in lymphoblastoid RNA derived from the patients and healthy control individuals. The CHRNE, DKFZP566H073, LOC90048, PFN1, SPAG7, KIAA0909, ZNF232 and KIF1C genes showed similar levels of expression in cell lines with the translocations when compared with cell lines with normal karyotype. No expression was detected for the MINK, GP1BA, SLC25A11, ENO3, FLJ10060 and USP6 genes in any of the cell lines. The close physical relation of the two 17p breakpoints suggest a common genetic aetiology for the phenotype in the patients. Structural and functional analysis of the genes located around the two 17p breakpoints in t(13;17) and t(17;19) patients may reveal candidate sequences for the AS phenotype.

Characterization of ZNF333, a novel double KRAB domain containing zinc finger gene on human chromosome 19p13.1

ZNF333 is a novel human KRAB-zinc finger protein gene on chromosome 19p13.1 encompassing 14 exons. ZNF333 is highly expressed in heart and encodes a 665 amino acid protein that contains a rare combination of double KRAB-domains, each consisting of a classical KRAB-A and a highly divergent KRAB-B box at the N-terminus. ZNF333 further contains 10 C2H2 zinc finger motifs at the C-terminus.

The SCAN domain of ZNF174 is a dimer

The SCAN domain is a conserved region of 84 residues found predominantly in zinc finger DNA-binding proteins in vertebrates. The SCAN domain appears to control the association of SCAN domain containing proteins into noncovalent complexes and may be the primary mechanism underlying partner choice in the oligomerization of these transcription factors. Here we have overexpressed, purified, and characterized the isolated SCAN domain (amino acids 37-132) from ZNF174. Both size exclusion chromatography and equilibrium sedimentation analysis demonstrate that the ZNF174 SCAN domain forms a homodimer. Circular dichroism shows that the isolated SCAN domain dimer has approximately 42% alpha-helix. Thermal denaturation experiments indicate that the SCAN domain undergoes a single reversible unfolding transition with a T(m) of over 70 degrees C. The midpoint of the equilibrium unfolding transition increases with increasing protein concentration, consistent with a two-state unfolding transition in which folded dimer is in equilibrium with unfolded monomer. These findings demonstrate that the isolated SCAN domain forms a stable dimer and support a model in which the SCAN domain is capable of mediating the selective dimerization of a large family of vertebrate-specific, zinc finger-containing transcription factors.