Characterization of a family of related cellular transcription factors which can modulate human immunodeficiency virus type 1 transcription in vitro.

Abstract

LBP-1 is a cellular protein which binds strongly to sequences around the human immunodeficiency virus type 1 (HIV-1) initiation site and weakly over the TATA box. We have previously shown that LBP-1 represses HIV-1 transcription by inhibiting the binding of TFIID to the TATA box. Four similar but distinct cDNAs encoding LBP-1 (LBP-la, -b, -c, and -d) have been isolated. These are products of two related genes, and each gene encodes two alternatively spliced products. Comparison of the amino acid sequence of LBP-1 with entries in the available protein data bases revealed the identity of LBP-lc to a-CP2, an a-globin transcription factor. These proteins are also homologous to Drosophila melanogaster Elf-1/NTF-1, an essential transcriptional activator that functions during Drosophila embryogenesis. Three of the recombinant LBP-1 isoforms show DNA binding specificity identical to that of native LBP-1 and bind DNA as a multimer. In addition, antisera raised against recombinant LBP-1 recognize native LBP-1 from HeLa nuclear extract. Functional analyses in a cell-free transcription system demonstrate that recombinant LBP-1 specifically represses transcription from a wild-type HIV-1 template but not from an LBP-1 mutant template. Moreover, LBP-1 can function as an activator both in vivo and in vitro, depending on the promoter context. Interestingly, one isoform of LBP-1 which is missing the region of the Elf-l/NTF-1 homology is unable to bind DNA itself and, presumably through heteromer formation, inhibits binding of the other forms of LBP-1, suggesting that it may function as a dominant negative regulator.

Intracellular domains of amyloid precursor-like protein 2 interact with CP2 transcription factor in the nucleus and induce glycogen synthase kinase-3β expression

“…32 By interacting with a hyphenated sequence composed of two directly repeated four base pair motifs repeated by a 6-bp linker (CNRG-N6-CNR [G/C]), a ubiquitously expressed CP2 transcription factor regulates some genes including GSK-3b, a-macroglobulin and certain factors involved in the inflammatory response that exert T-cell responses when subjected to mitogenic stimulation. 20,32 A previous report showed that the A allele of the 3 0 -UTR CP2 gene polymorphism has been reported to increase the risk of sporadic AD. 33 We examined the effects of APLP2-ICDs on the expression of GSK-3b, a gene known to be regulated by the CP2 transcription factor.…”

Identification and characterization of Grainyhead‐like epithelial transactivator (GET‐1), a novel mammalian Grainyhead‐like factor

“…These are as follows: (1) CP-2 (Lim et al, 1992(Lim et al, , 1993Shirra et al, 1994), also referred to as UBP-1, LSF, LBP-1c, and LBP-1d (alternatively spliced form), a widely expressed transcription factor that has been implicated in activation of the ␣-globin gene (Chodosh et al, 1988;Kim et al, 1990), the HIV-1 long terminal repeat (LTR; Jones et al, 1988;Wu et al, 1988;Malim et al, 1989;Kato et al, 1991), and the SV40 major late promoter (Kim et al, 1987;Huang et al, 1990). This factor can also, depending on context, repress transcription and was shown to cooperate with YY1 to repress HIV-1 LTR activity (Coull et al, 2000); (2) LBP-1a (Sueyoshi et al, 1995), also referred to as LBP-1b (alternatively spliced form) and NF2d9 (Yoon et al, 1994), a widely expressed factor implicated in regulation of the HIV-1 LTR (Yoon et al, 1994) and a P450 gene (Sueyoshi et al, 1995); (3) LBP-9 (Huang and Miller, 2000), also referred to as CP2-related transcriptional Repressor-1 (CRTR-1; Rodda et al, 2001), implicated in regulation of the P450 scc promoter; (4) LBP-32 (Huang and Miller, 2000), also refer- . Grainyhead-like epithelial transactivator 1 (GET-1) transcripts are highly expressed in epithelial cells of the mouse embryo and persist in adult mice.…”

Gene trap screening as an effective approach for identification of Wnt‐responsive genes in the mouse embryo

“…In vertebrates, this family consists of several members, including CRTR-1 (known as LBP-9 in human; Huang and Miller, 2000), CP2 (also known as LBP-1c and LSF; Lim et al, 1992;Shirra et al, 1994), NF2d9 (known as LBP-1a in human; Sueyoshi et al, 1995;Yoon et al, 1994), mammalian Grainyhead (MGR), brother of MGR (BOM; Wilanowski et al, 2002), sister of MGR (SOM)/GET1 (Kudryavtseva et al, 2003;Ting et al, 2003b), but their developmental roles have been largely unknown (Ramamurthy, 2001;Ting et al, 2003a). We found that CRTR-1 was specifically expressed in the ductal epithelium of the kidney and the salivary glands (Fig.…”