Characterization of NERF, a Novel Transcription Factor Related to the Ets Factor ELF-1

Abstract

We have cloned the gene for a novel Ets-related transcription factor, new Ets-related factor (NERF), from human spleen, fetal liver, and brain. Comparison of the deduced amino acid sequence of NERF with those of other members of the Ets family reveals that the level of homology to ELF-1, which is involved in the regulation of several T-and B-cell-specific genes, is highest. Homologies are clustered in the putative DNA binding domain in the middle of the protein, a basic domain just upstream of this domain, and several shorter stretches of homology towards the amino terminus. The presence of two predominant NERF transcripts in various fetal and adult human tissues is due to at least three alternative splice products, NERF-1a, NERF-1b, and NERF-2, which differ in their amino termini and their expression in different tissues. Only NERF-2 and ELF-1, and not NERF-1a and NERF-1b, function as transcriptional activators of the lyn and blk gene promoters, although all isoforms of NERF bind with affinities similar to those of ELF-1 to a variety of Ets binding sites in, among others, the blk, lck, lyn, mb-1, and immunoglobulin H genes and are expressed at similar levels. Since NERF and ELF-1 are coexpressed in B and T cells, both might be involved in the regulation of the same genes.In our search for transcriptional regulators of B-cell differentiation we have observed that the majority of B-cell-specific genes contain ets-related enhancer elements in their regulatory regions (4). We, therefore, have focused on characterizing the members of the ets transcription factor/oncogene family which are involved in B-cell gene regulation. The ets gene family traces its history to oncogenes cloned from retroviruses (89). Since the time of this original cloning, more than 20 cellular homologs which function as transcription factors under physiological conditions and transform cells when aberrantly expressed have been cloned (36,89). All members of the Ets family share a highly conserved 80-to 90-amino-acid DNA binding domain, the Ets domain. The Ets domain is sufficient to interact specifically with DNA sequences, and because of the conserved DNA binding domain, binding sites for ets factors are all very similar, with a core binding motif, A/GGAA/T, and slight differences in flanking nucleotides for different ets factors (36,89). Outside the DNA binding domain very little homology is common to all members of the Ets family. Etsrelated proteins can be grouped into subclasses based on additional homologous domains unique for particular members of the Ets family (36, 89). Thus, for example, ERP, SAP-1, and ELK-1 are grouped together because of three homology regions outside the Ets domain which are not found in other members of the Ets family (16, 55).The role of ets factors in human carcinogenesis was recently established when several members of the Ets family were directly implicated in specific chromosomal translocations in different types of cancer. Ewing's sarcoma is characterized by translocations involving either erg, fli-1, or E...

Phosphorylation and O-Linked Glycosylation of Elf-1 Leads to Its Translocation to the Nucleus and Binding to the Promoter of the TCR ζ-Chain

“…P32519) contains an open reading frame of 1,857 nt and therefore encodes a protein of 619 aa with an expected molecular mass of 68 kDa. However, most of the published work indicates that Elf-1 exists as a protein with an apparent molecular mass of 98 kDa, although 80-kDa and 68-kDa forms have also been mentioned (1,8). Interestingly, this discrepancy in the apparent molecular mass is not limited to Elf-1 and characterizes other Ets family members.…”

“…Interestingly, this discrepancy in the apparent molecular mass is not limited to Elf-1 and characterizes other Ets family members. Nerf, an Ets familyrelated protein, has a calculated molecular mass of 58 kDa, but it migrates as a 69-kDa protein (1). Proteins that contain a high ratio of either positively or negatively charged amino acids are known to display discrepancies between the estimated molecular mass and that observed by SDS gel electrophoresis.…”

A novel epithelial-expressed ETS gene, ELF3: human and murine cDNA sequences, murine genomic organization, human mapping to 1q32.2 and expression in tissues and cancer

“…ETS proteins are indicated with a species pre®x; D (Drosophila), H (human), M (mouse). Proteins examined include: E74A (Burtis et al, 1990), ELF1 , NERF (Oettgen et al, 1996), PEP1 , ETS4 (Chen et al, 1992), YAN (Lai and Rubin, 1992), TEL (Golub et al, 1994), ELK1 (Rao et al, 1989), ERP , SAP1 (Dalton and Treisman, 1992), ER71 (Brown and McKnight, 1992), ERG (Rao et al, 1987), FLI1 (Ben-David et al, 1991), ETS6 (Chen et al, 1992), ETS1 (Chen, 1990), ETS2 (Watson et al, 1988), GABPa (LaMarco et al, 1991), ELG , ER81 (Monte et al, 1995), ERM (Monte et al, 1994), PEA3 (Xin et al, 1992), ETS3 (Chen et al, 1992), PU1 (Klemsz et al, 1990), and SPIB (Ray et al, 1992). Amino acids with identity to ELF3 are shaded.…”

ESE-3, a Novel Member of an Epithelium-specific Ets Transcription Factor Subfamily, Demonstrates Different Target Gene Specificity from ESE-1

“…Human tissue RNA blots (2 g of poly(A) ϩ RNA loaded/lane) and a master Northern blot containing poly(A) ϩ RNA from 49 different sources were purchased from CLONTECH, hybridized, and analyzed by autoradiography according to standard procedures as described (35).…”

“…To determine the 5Ј end of ESE-3, we performed the 5Ј RACE method using human adult prostate cDNA ready for RACE (Marathon ready cDNA, CLON-TECH) and nested primers specific for the partial ESE-3 cDNA, N1 (5Ј-CCCTCGAGGTCGACGGTATCGATA-3Ј) and N2 (5Ј-GGCTCTT-GCTGGGGTCAAGAGGAT-3Ј) as described (35). Amplified DNA fragments were subcloned and sequenced as described (35). The 5Ј end sequence of the ESE-3 cDNA was confirmed by repeating 5Ј-RACE PCR amplification using primers specific for the 5Ј end of the longest 5Ј-RACE products obtained in the first two rounds of PCR amplification.…”