A gene from the VSG expression site ofTrypanosoma bruceiencodes a protein with both leucine-rich repeats and a putative zinc finger

The nitrogen regulatory circuit of Neurospora crassa consists of a set of unlinked structural genes which specify various nitrogen catabolic enzymes plus control genes and metabolic effectors which regulate their expression. The positive-acting nit-2 regulatory gene is required to turn on the expression of the nitrogen catabolic enzymes during conditions of nitrogen limitation. The complete nucleotide sequence of the nit-2 gene was determined. The nit-2 mRNA is 4.3 kilobases long and has a long nontranslated sequence at both its 5' and 3' ends. The nit-2 gene nucleotide sequence can be translated to yield a protein containing 1,036 amino acid residues with a molecular weight of approximately 110,000. Deletion analyses demonstrated that approximately 21% of the NIT2 protein at its carboxy terminus can be removed without loss of function. The nit-2 protein contains a single putative Cys2/Cys2 zinc finger domain which appears to function in DNA binding and which has striking homology to a mammalian trans-acting factor, GF-1.

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The trypanosome leucine repeat gene in the variant surface glycoprotein expression site encodes a putative metal-binding domain and a region resembling protein-binding domains of yeast, Drosophila, and mammalian proteins

Molecular and Cellular Biology ◽

10.1128/mcb.10.12.6436-6444.1990 ◽

1990 ◽

Vol 10 (12) ◽

pp. 6436-6444

Author(s):

B L Smiley ◽

A W Stadnyk ◽

P J Myler ◽

K Stuart

Keyword(s):

Nucleic Acid ◽

Adenylate Cyclase ◽

Metal Binding ◽

Surface Glycoprotein ◽

Variant Surface Glycoprotein ◽

Nucleic Acid Binding ◽

Leucine Rich Repeat ◽

Binding Domains ◽

Expression Site ◽

Leucine Rich Repeats

We have identified a new variant surface glycoprotein expression site-associated gene (ESAG) in Trypanosoma brucei, the trypanosome leucine repeat (T-LR) gene. Like most other ESAGs, it is expressed in a life cycle stage-specific manner. The N-terminal 20% of the predicted T-LR protein resembles the metal-binding domains of nucleic acid-binding proteins. The remainder is composed of leucine-rich repeats that are characteristic of protein-binding domains found in a variety of other eucaryote proteins. This is the first report of leucine-rich repeats and potential nucleic acid-binding domains on the same protein. The T-LR gene is adjacent to ESAG 4, which has homology to the catalytic domain of adenylate cyclase. This is intriguing, since yeast adenylate cyclase has a leucine-rich repeat regulatory domain. The leucine-rich repeat and putative metal-binding domains suggest a possible regulatory role that may involve adenylate cyclase activity or nucleic acid binding.

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Sequence and expression of GLN3, a positive nitrogen regulatory gene of Saccharomyces cerevisiae encoding a protein with a putative zinc finger DNA-binding domain

Molecular and Cellular Biology ◽

10.1128/mcb.11.12.6216-6228.1991 ◽

1991 ◽

Vol 11 (12) ◽

pp. 6216-6228 ◽

Cited By ~ 1

Author(s):

P L Minehart ◽

B Magasanik

Keyword(s):

Saccharomyces Cerevisiae ◽

Zinc Finger ◽

Regulatory Gene ◽

Null Alleles ◽

Gene Encoding ◽

Reading Frame ◽

Activation Of Transcription ◽

Initiation Of Translation ◽

Putative Zinc Finger ◽

Activation Sequence

The GLN3 gene of Saccharomyces cerevisiae is required for the activation of transcription of a number of genes in response to the replacement of glutamine by glutamate as source of nitrogen. We cloned the GLN3 gene and constructed null alleles by gene disruption. GLN3 is not essential for growth, but increased copies of GLN3 lead to a drastic decrease in growth rate. The complete nucleotide sequence of the GLN3 gene was determined, revealing one open reading frame encoding a polypeptide of 730 amino acids, with a molecular weight of approximately 80,000. The GLN3 protein contains a single putative Cys2/Cys2 zinc finger which has homology to the Neurospora crassa NIT2 protein, the Aspergillus nidulans AREA protein, and the erythroid-specific transcription factor GATA-1. Immunoprecipitation experiments indicated that the GLN3 protein binds the nitrogen upstream activation sequence of GLN1, the gene encoding glutamine synthetase. Neither control of transcription nor control of initiation of translation of GLN3 is important for regulation in response to glutamine availability.

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Structure, chromosome location, and expression of the mouse zinc finger gene Krox-20: multiple gene products and coregulation with the proto-oncogene c-fos

Molecular and Cellular Biology ◽

10.1128/mcb.9.2.787-797.1989 ◽

1989 ◽

Vol 9 (2) ◽

pp. 787-797 ◽

Cited By ~ 1

Author(s):

P Chavrier ◽

U Janssen-Timmen ◽

M G Mattéi ◽

M Zerial ◽

R Bravo ◽

...

Keyword(s):

Zinc Finger ◽

Chromosome 10 ◽

Sequence Element ◽

Multiple Gene ◽

Serum Stimulation ◽

Essential Components ◽

Encoding Gene ◽

Serum Response ◽

Putative Zinc Finger ◽

Cognate Protein

We have analyzed the structure and the regulation of Krox-20, a mouse zinc finger-encoding gene which is transiently activated following serum stimulation of quiescent fibroblast cells in culture. The gene is localized on chromosome 10, band B5, in the mouse, and the homologous human gene also maps to chromosome 10 (region q21.1 to q22.1). Alternative splicing of the 5'-most intron of the Krox-20 gene gives rise to mRNAs encoding putative zinc finger proteins with different N termini. The first exon contains a sequence element with strong similarity to the c-fos proto-oncogene serum response element (SRE). This element can functionally substitute for the c-fos SRE, and it binds the same nuclear protein. It is probably responsible for the serum induction of Krox-20, possibly in combination with a weaker SRE located in the 5'-flanking region of the gene. Our findings suggest that c-fos, Krox-20, and a number of immediate-early serum response genes are coregulated and that the SRE and its cognate protein are essential components of this regulatory pathway.

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