Pet-1, a Novel ETS Domain Factor That Can Activate Neuronal nAchR Gene Transcription Dmitry Fyodorov, Tom Nelson, Evan Deneris Department of Neurosciences, School of Medicine, 2109 Adelbert Rd., Case Western Reserve University, Cleveland, Ohio 44106 Received 12 August 1997; accepted 15 September 1997 moter constructs in a sequence-specific manner. We ABSTRACT: We report a cDNA clone prepared recently identified a neural cell-type specific enhancer, from adrenal chromaffin-derived PC12 cell RNA that b43 , within the 3 -untranslated exon of the neuronal encodes a novel ETS-domain factor, Pet-1. The de- nicotinic acetylcholine receptor ( nAchR ) b4 subunit duced primary structure of Pet-1 is composed of 340 gene. Similar to Pet-1, the b4 gene is also expressed amino acids and the encoded polypeptide has a pre- in PC12 cells. The presence of putative ETS-domain dicted molecular mass of 35.4 kD. The pattern of Pet- binding sites in the b43  enhancer led us to hypothe- 1 gene expression in the neonatal rat is highly re- size that members of the ets gene family activate neu- stricted and suggests that Pet-1 functions primarily in ronal nAchR genes. Cotransfection assays show that the nervous system. Adrenal gland expresses the high- Pet-1 can activate reporter gene transcription in a est level of Pet-1 among the tissues examined. In situ b43  enhancer-dependent and cell type – dependent hybridization indicates that Pet-1 is expressed in the manner. Our results lead us to hypothesize that Pet- adrenal medulla but not the adrenal cortex. Slightly 1 acts as a transcriptional regulator of downstream weaker Pet-1 hybridization is detected in brain and target genes involved in cholinergic neurotransmis- low levels are detectable in intestine and eye. Pet-1 sion.  1998 John Wiley & Sons, Inc. J Neurobiol 34: 151–163, can bind specifically to a PEA3 ETS DNA-binding 1998 motif and can modulate transcription of synthetic pro- INTRODUCTION to regulate neural cell-type identity in specific re- gions of both the vertebrate and invertebrate ner- vous systems. Many of these genes are expressed The enormous phenotypic diversity of neural cell early in neural development, which suggests they types implies a corresponding complexity of gene- play a critical role in neurogenesis and neuronal specific transcription factor combinations required patterning (Tanabe and Jessell, 1996). However, to regulate thousands of genes in the appropriate our understanding of the functional interplay be- stage and cell type – specific manner ( He and Rosen- tween different transcription factors and the neural feld, 1991; Mandel and McKinnon, 1993; Struhl, genes they regulate is just beginning to emerge. 1991). Indeed, several members of different tran- Furthermore, we know little about the identity and scription factor classes, such as homeodomain, zinc- specific functions of transcription factors which op- finger, and basic helix-loop-helix proteins, function erate at later stages of neural development to com- plete particular differentiation programs involved in the appearance and maintenance of specific neural Correspondence to: E. Deneris cell phenotypes. Contract grant sponsor: NIH; contract grant number: RO1 ETS domain proteins are a class of sequence- NS29123  1998 John Wiley & Sons, Inc. CCC 0022-3034/98/020151-13 specific transcription factors that are also important 151 1916 / 8P35$$1916 12-15-97 09:09:48 nbioa W: Neurobio