Gina Pengue

cDNA isolation, expression analysis, and chromosomal localization of two human zinc finger genes ☆

On the basis of sequence similarity in the repeated zinc finger domain, we have identified and characterized two human cDNA clones (ZNF7 and ZNF8), both encoding proteins containing potential finger-like nucleic acid binding motifs. Northern blot analysis indicates that both genes are expressed as multiple transcripts and they are ubiquitously present in many human cell lines of different embryological derivation. Moreover, their expression is modulated during in vitro induced terminal differentiation of human myeloid cell line HL-60. By in situ hybridization experiments, we have localized the ZNF7 gene to chromosome 8 (region q24) and the ZNF8 gene to the terminal band of the long arm of chromosome 20 (20q13).

The Ability of the Inhibitory Domain of the POU Family Transcription Factor Oct-2 to Interfere with Promoter Activation by Different Classes of Activation Domains Is Dependent upon the Nature of the Basal Promoter Elements

The Oct-2 transcription factor contains an inhibitory domain which is able to repress transcription following DNA binding. Here we show that within the neuronally expressed Oct-2.5 form, the inhibitory domain can strongly inhibit activation by transcription factor activation domains which are either composed predominantly of acidic residues or contain the HOB motif, whereas it has a weaker effect or no effect on proline-rich activation domains and on a glutamine-rich domain. In contrast, the isolated inhibitory domain of Oct-2 can efficiently repress all types of activation domains. This effect is observed however, only on TATA box-containing promoters and not on promoters containing an initiator motif. This widespread inhibition of different activation domains and its dependence on the nature of the basal promoter elements indicate that the inhibitory domain is likely to act by contacting a common downstream target of activation domains within the basal transcriptional complex bound at the TATA box rather than quenching specific activation domains by direct interaction. These effects are discussed in terms of the functional role of the inhibitory domain within Oct-2.5 and the mechanism by which it acts.

Localization of the human HF.10 finger gene on a chromosome region (3p21–22) frequently deleted in human cancers

SummaryThe finger motif is a tandemly repeated DNA-binding domain recently identified in the primary structure of several eukaryotic transcriptional regulatory proteins. It has been proposed that some members of the finger-gene family are implicated in both normal cell proliferation and differentiation. We isolated several human finger genes by means of hybridization with a finger motif-containing DNA probe. One of these finger genes, HF.10, is expressed at low levels in a variety of human tissues and is down-regulated during the in vitro terminal differentiation of human leukemic myeloid cell lines. By in situ hybridization experiments and analysis of interspecific somatic cell hybrids we mapped the HF.10 gene to 3p21–22, a chromosome region frequently involved in karyotypic rearrangements associated with lung and renal cancer.

Positional cloning of cDNAs from the human chromosome 3p21-22 region identifies a clustered organization of zinc-finger genes.

The human 3p21-22 region is frequently involved in karyotype rearrangements associated with malignancies. The high frequency of allelic loss in this region has been associated with virtually all small cell lung carcinomas and many renal carcinomas. These findings suggest that at least one tumor-suppressor gene might be located in 3p21-22. We have recently reported the isolation of a 750-kb yeast artificial chromosome (YAC) contig from 3p21-22. Here, we describe three new genes isolated from the 3p YAC contig by using a cDNA hybridization selection. Remarkably, the three new genes encode zinc-finger proteins, indicating the presence of a cluster of zinc-finger genes in human chromosome 3p21.

Chromosomal localization of four human zinc finger cDNAs

AbstractcDNA clones encoding zinc finger motifs were isolated by screening human placenta and T-cell (Peer) cDNA libraries with zinc finger (ZNF) consensus sequences. Unique cDNA clones were mapped in the human genome by rodent-human somatic cell hybrid analysis and in some cases in situ chromosomal hybridization. ZNF 80 mapped to 3p12-3qter, ZNF 7 was previously mapped to 8q24 and is here shown by in situ hybridization and use of appropriate hybrids to map telomeric to the MYC locus. ZNF 79 mapped to 9q34 centromeric to the ABL gene and between a constitutional chromosomal translocation on the centromeric side and the CML specific ABL translocation on the telomeric side. ZNF77 mapped to 19p while ZNF 78L1 (pT3) mapped to 19q. Chromosome 19 carries many ZNF loci and other genes with zinc finger encoding motifs; the pT3 clone additionally detected a locus designated ZNF 78L2, which mapped to chromosome region 1p, most likely in the region 1p32 where the MYCL and JUN loci map.

Transiently transfected and stably integrated HIV-1 LTR responds differentially to the silencing activity of the krüppel-associated box (KRAB) transcriptional repressor domain

It has been demonstrated previously that the transcriptional repressor domain called the Krüppel‐associated box (KRAB), conserved in a large number of Krüppel‐type zinc finger proteins, fused to Tat transdominant negative mutants, is able to silence HIV‐1 long terminal repeat (LTR)‐driven gene expression in transient transfection assays. In the present study chimeric Tat mutant‐KRAB retroviral expression vectors were used to control HIV‐1 replication in acutely infected cells. It was found that while transient and stable expression of Tat mutant‐KRAB chimeric proteins represses HIV‐1 LTR‐driven gene transcription in transient assays, stable expression of Tat mutant‐KRAB chimeric molecules does not confer resistance to HIV‐1 infection in Jurkat T lymphocytic cell lines. The results provide further evidence that transient transfection may underestimate the role of chromosomal structure in transcriptional regulation and highlight the caveat of direct extrapolation of transient results for designing gene therapy strategies for efficient control of HIV‐1 infection. J. Med. Virol. 58:264–272, 1999.