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TOBFAC: The database of tobacco transcription factors

Family: Nin

Minimum number of tobacco Nin-like genes: 11

Count of tobacco Nin-like sequences: 13

Pfam accession:

Nodule inception initially relies on cell competence in a narrow infection zone located just behind the growing root tip. Older nodules then regulate the number of nodules on a root system by suppressing the development of nodule primordia. Nin (for nodule inception) is required for the formation of infection threads and the initiation of primordia. NIN protein has regional similarity to transcription factors, and the predicted DNA-binding/dimerization domain identifies and typifies a consensus motif conserved in plant proteins with a function in nitrogen-controlled development.

The full-length Nin cDNA has an open reading frame of 2,634 bp, a 5' leader with stop codons in all three reading frames, and a 3' untranslated region of 141 bp. The protein, comprising 878 amino acids, is shown in Fig. 3a along with a diagram of several domains with similarity to transcription factors. The carboxy-terminal half of the protein carries an unusual putative DNA-binding domain with a basic region followed by two heptad leucine or isoleucine repeats (R1 and R2); an amphiphatic leucine-zipper structure was predicted for R2 by helical-wheel analysis (Fig. 3). This arrangement is similar to the DNA-binding/dimerization domains of the bZIP8 and bHLH/Z9 transcription factors, but the R1/R2 region does not comply with a strict consensus of either domain. The distance between the basic region and the zipper, for example, is longer than would be expected from the bZIP consensus. The presence of a proline helix breaker (Pro 597) in R1 also distinguishes NIN, and alignment to prokaryotic helix¨Cturn¨Chelix DNA-binding domains10 suggests a GV turn motif preceding Pro 597 (not shown). No known DNA-binding/dimerization domains combine these components, and the structure of the domain has yet to be resolved by crystallography. Two acidic domains located between residues 428¨C503 and 826¨C845 may function as transcriptional activation domains. Supporting the role as a transcription factor, NIN has SV40-like and bipartite nuclear localization signals11 (Fig. 3). Less clear is the role of a hexaglutamine stretch between residues 9¨C14 and five double and eight single glutamine residues within the first 420 amino acids.

The nitrogen regulation of nodule organogenesis and Chlamydomonas gametogenesis together with the conserved domain embedding the RWP¨CRK motif of NIN and Mid indicate that this domain is involved in the regulation of genes controlled by nitrogen status. Because the conserved domain was found only in proteins from algae and higher plants, this class of regulator proteins probably evolved after the common ancestor of algae and plants diverged from the other eukaryotes.

Papers

Schauser L, Roussis A, Stiller J, Stougaard J. A plant regulator controlling development of symbiotic root nodules Nature. 1999 Nov 11;402(6758):191-5. PMID: 10647012

Number of contigs: 11

Number of singlets: 4

Number of N terminal – 2

Number of C terminal – 5

Number of full – 6

Total minimum number – 11

Search sequences and info

Transcription factor sequences

Tobacco published genes related to transcription factor family Nin

Authors of this site:

Paul J Rushton
Marta T. Bokowiec
Xianfeng (Jeff) Chen
Thomas (Tom) W Laudeman
Jennifer F. Brannock
Michael P. Timko

Contact:

pr8y@virginia.edu