cDNA isolation, genomic structure, regulation, and chromosomal localization of human lung Kruppel-like factor.

Lung Kruppel-like factor (LKLF) is a zinc finger transcription factor critical for embryonic development. We have previously identified and isolated the mouse LKLF gene and examined its role using gene targeting. In this report, we describe the isolation and molecular characterization of the human homolog of murine LKLF. The human and mouse LKLF homologs exhibit an 85% nucleotide identity and share 90% amino acid similarity. Furthermore, the 5' sequence in the proximal promoter region and 3' untranslated region are also conserved between the two species. Of particular interest is the finding that while sequences in the proximal promoter have diverged between mouse and human, a region of 75 nucleotides is essentially identical. Site-directed mutagenesis in this region impairs the ability of the LKLF promoter to drive reporter gene expression, indicating that it represents a novel transcriptional element important in the regulation of LKLF gene expression. The activation domain is highly proline-rich and, similar to mouse LKLF, contains 22% proline residues. The human LKLF transcriptional unit is located in a genomic region of approximately 3 kb on chromosome 19p13.1. This region of chromosome 19 is known to contain genes involved in various human diseases. Like mouse LKLF, human LKLF consists of three exons that are interrupted by two small introns. The locations of intron/exon boundaries and splice sites are conserved between two homologs. Northern analysis shows that LKLF is expressed in lung in addition to heart, skeletal muscle, placenta, and pancreas. The isolation and chromosomal mapping of human LKLF will make it possible to initiate studies devoted to assess the involvement of this gene in human disease(s).

Wani MA ，Conkright MD ，Jeffries S ，Hughes MJ ，Lingrel JB ... -  《GENOMICS》

Cloning and characterization of ZNF189, a novel human Krüppel-like zinc finger gene localized to chromosome 9q22-q31.

Odeberg J ，Røsok O ，Gudmundsson GH ，Ahmadian A ，Roshani L ，Williams C ，Larsson C ，Pontén F ，Uhlén M ，Asheim HC ，Lundeberg J ... -  《GENOMICS》

Cloning and characterization of ZNF236, a glucose-regulated Kruppel-like zinc-finger gene mapping to human chromosome 18q22-q23.

We report the cDNA cloning and characterization of ZNF236, a novel Kruppel-like zinc-finger gene initially identified by its glucose-regulated expression in human mesangial cells using mRNA differential display. Using the differential display fragment as a probe, we screened a human fetal kidney cDNA library and isolated several clones representing two differently spliced mRNA transcripts, designated ZNF236a and -b. Both transcripts were identical apart from the presence of an additional exon in ZNF236a that truncates the open reading frame. RT-PCR analysis confirmed the expression of both transcripts to be upregulated in human mesangial cells in response to elevated levels of d-glucose. ZNF236a and -b cDNAs encode polypeptides of 174 and 204 kDa, containing 25 and 30 C(2)H(2) zinc-finger motifs, respectively. Northern blot analysis showed that ZNF236 is ubiquitously expressed in all human tissues tested. Expression levels were highest in skeletal muscle and brain, intermediate in heart, pancreas, and placenta, and lowest in kidney, liver, and lung. Southern zoo blot analysis indicated that ZNF236 is conserved in the genomes of all mammalian species tested, but not in yeast. The mapping of ZNF236 to human chromosome 18q22-q23, close to the IDDM6 locus, coupled with the glucose-regulated expression of the gene in human mesangial cells, suggests that ZNF236 may be a candidate gene for diabetic nephropathy.

Holmes DI ，Wahab NA ，Mason RM 《GENOMICS》

Isolation and characterization of a novel gene from the DiGeorge chromosomal region that encodes for a mediator subunit.

Hemizygous deletions on chromosome 22q11.2 result in developmental disorders referred to as DiGeorge syndrome (DGS)/velocardiofacial syndrome (VCFS). We report the isolation of a novel gene, PCQAP (PC2 glutamine/Q-rich-associated protein), that maps to the DiGeorge typically deleted region and encodes a protein identified as a subunit of the large multiprotein complex PC2. PC2 belongs to the family of the human Mediator complexes, which exhibit coactivator function in RNA polymerase II transcription. Furthermore, we cloned the homologous mouse Pcqap cDNA. There is 83% amino acid identity between the human and the mouse predicted protein sequences, with 96% similarity at the amino- and carboxy-terminal ends. To assess the potential involvement of PCQAP in DGS/VCFS, its developmental expression pattern was analyzed. In situ hybridization of mouse embryos at different developmental stages revealed that Pcqap is ubiquitously expressed. However, higher expression was detected in the frontonasal region, pharyngeal arches, and limb buds. Moreover, analysis of subjects carrying a typical 22q11 deletion revealed that the human PCQAP gene was deleted in all patients. Many of the structures affected in DGS/VCFS evolve from Pcqap-expressing cells. Together with the observed haploinsufficiency of PCQAP in DGS/VCFS patients, this finding is consistent with a possible role for this novel Mediator subunit in the development of some of the structures affected in DGS/VCFS.

Berti L ，Mittler G ，Przemeck GK ，Stelzer G ，Günzler B ，Amati F ，Conti E ，Dallapiccola B ，Hrabé de Angelis M ，Novelli G ，Meisterernst M ... -  《GENOMICS》

[cDNA cloning, subcellular localization and tissue expression of a new human Krüppel-like transcription factor: human basic Krüppel-like factor (hBKLF)].

Wang MJ ，Qu XH ，Wang LS ，Zhai Y ，Wu SL ，He FC ... -  《-》