scholarly journals Leucine-zipper motif update

Nature ◽  
1989 ◽  
Vol 340 (6229) ◽  
pp. 103-103 ◽  
Author(s):  
KEN McCoRMACK ◽  
JAMES T. CAMPANELLI ◽  
MANI RAMASWAMI ◽  
MATHEW K. MATHEW ◽  
MARK A. TANOUYE ◽  
...  
Keyword(s):  
Leucine Zipper ◽  
Leucine Zipper Motif

scholarly journals Mating Type in Chlamydomonas Is Specified by mid, the Minus-Dominance Gene

Genetics ◽  
1997 ◽  
Vol 146 (3) ◽  
pp. 859-869 ◽  
Author(s):  
Patrick J Ferris ◽  
Ursula W Goodenough
Keyword(s):  
Transcription Factor ◽  
Mating Type ◽  
Codon Bias ◽  
Leucine Zipper ◽  
Laboratory Strain ◽  
Leucine Zipper Motif ◽  
Type Locus ◽  
Diploid Cells ◽  
Necessary And Sufficient

Diploid cells of Chlamydomonas reinhardtii that are heterozygous at the mating-type locus (mt  +/mt  –) differentiate as minus gametes, a phenomenon known as minus dominance. We report the cloning and characterization of a gene that is necessary and sufficient to exert this minus dominance over the plus differentiation program. The gene, called mid, is located in the rearranged (R) domain of the mt  – locus, and has duplicated and transposed to an autosome in a laboratory strain. The imp11 mt  – mutant, which differentiates as a fusion-incompetent plus gamete, carries a point mutation in mid. Like the fus1 gene in the mt  + locus, mid displays low codon bias compared with other nuclear genes. The mid sequence carries a putative leucine zipper motif, suggesting that it functions as a transcription factor to switch on the minus program and switch off the plus program of gametic differentiation. This is the first sex-determination gene to be characterized in a green organism.

scholarly journals A gene that is related to SRY and is expressed in the testes encodes a leucine zipper-containing protein.

1995 ◽  
Vol 15 (7) ◽  
pp. 3759-3766 ◽  
Author(s):  
N Takamatsu ◽  
H Kanda ◽  
I Tsuchiya ◽  
S Yamada ◽  
M Ito ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Cdna Library ◽  
Cho Cells ◽  
Leucine Zipper ◽  
Leucine Zipper Motif ◽  
Hmg Box ◽  
Testis Cdna Library ◽  
Testis Cdna

SRY-related cDNA encoding a protein with a high-mobility-group (HMG) box and a leucine zipper motif, which was designated SOX-LZ, was isolated from a rainbow trout testis cDNA library. Comparison of this cDNA with the mouse homologous cDNA isolated from a testis cDNA library exhibits an overall amino acid sequence identity of 77%, which is in striking contrast to the abrupt loss of amino acid sequence homology outside the HMG box found among mammalian SRY genes. In both rainbow trout and mice, Northern (RNA) blot analyses have revealed the presence of a testis-specific 3-kb-long SOX-LZ mRNA, and this transcript appeared coincidentally with the protamine mRNA, suggesting its expression in the germ line. A recombinant HMG box region protein encoded by SOX-LZ could bind strongly with an oligonucleotide containing an AACAAT sequence, which is also recognized by mouse Sry and Sox-5. Upon cotransfection into CHO cells, SOX-LZ transactivated transcription through its binding motif when the region including the leucine zipper motif was deleted [SOX-LZ (D105-356)]; however, the intact SOX-LZ failed to transactivate. The intact SOX-LZ could form homodimers through the leucine zipper, which resulted in inhibition of DNA binding by the HMG box, while SOX-LZ (D105-356), which was incapable of dimerization, showed specific binding with the AACAAT sequence. Thus, the repressed transactivation of the intact SOX-LZ in CHO cells was primarily attributable to the low level of DNA binding of SOX-LZ homodimers.

scholarly journals Dimerization mediated through a leucine zipper activates the oncogenic potential of the met receptor tyrosine kinase.

1993 ◽  
Vol 13 (11) ◽  
pp. 6711-6722 ◽  
Author(s):  
G A Rodrigues ◽  
M Park
Keyword(s):  
Tyrosine Kinase ◽  
Receptor Tyrosine Kinase ◽  
Tyrosine Kinases ◽  
Leucine Zipper ◽  
Kinase Domain ◽  
Site Directed Mutagenesis ◽  
Leucine Zipper Motif ◽  
Transforming Activity ◽  
Met Oncogene ◽  
Hepatocyte Growth

Oncogenic activation of the met (hepatocyte growth factor/scatter factor) receptor tyrosine kinase involves a genomic rearrangement that generates a hybrid protein containing tpr-encoded sequences at its amino terminus fused directly to the met-encoded receptor kinase domain. Deletion of Tpr sequences abolishes the transforming ability of this protein, implicating this region in oncogenic activation. We demonstrate, by site-directed mutagenesis and coimmunoprecipitation experiments, that a leucine zipper motif within Tpr mediates dimerization of the tpr-met product and is essential for the transforming activity of the met oncogene. By analogy with ligand-stimulated activation of receptor tyrosine kinases, we propose that constitutive dimerization mediated by a leucine zipper motif within Tpr is responsible for oncogenic activation of the Met kinase. The possibility that this mechanism of activation represents a paradigm for a class of receptor tyrosine kinase oncogenes activated by DNA rearrangement is discussed.

scholarly journals Homodimerization via a Leucine Zipper Motif Is Required for Enzymatic Activity of Quiescent Cell Proline Dipeptidase

2000 ◽  
Vol 275 (35) ◽  
pp. 26994-26999
Author(s):  
Murali Chiravuri ◽  
Henry Lee ◽  
Suzanne L. Mathieu ◽  
Brigitte T. Huber
Keyword(s):  
Enzymatic Activity ◽  
Leucine Zipper ◽  
Quiescent Cell ◽  
Leucine Zipper Motif

scholarly journals Interaction of a Swi3 homolog with Sth1 provides evidence for a Swi/Snf-related complex with an essential function in Saccharomyces cerevisiae.

1997 ◽  
Vol 17 (4) ◽  
pp. 1768-1775 ◽  
Author(s):  
I Treich ◽  
M Carlson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Hybrid System ◽  
Transcriptional Activation ◽  
Leucine Zipper ◽  
Leucine Zipper Motif ◽  
Cell Extracts ◽  
Essential Function ◽  
Self Association ◽  
Two Hybrid

The Saccharomyces cerevisiae Swi/Snf complex has a role in remodeling chromatin structure to facilitate transcriptional activation. The complex has 11 components, including Swi1/Adr6, Swi2/Snf2, Swi3, Snf5, Snf6, Snf11, Swp73/Snf12, and Tfg3. Mammalian homologs of these proteins have been shown to form multiple Swi/Snf-related complexes. Here we characterize an S. cerevisiae Swi3 homolog (Swh3) and present evidence that it associates in a complex with a Snf2 homolog, Sthl. We identified Swh3 as a protein that interacts with the N terminus of Snf2 in the two-hybrid system. Swh3 and Swi3 are functionally distinct, and overexpression of one does not compensate for loss of the other. Swh3 is essential for viability and does not activate transcription of reporters. The Snf2 sequence that interacts with Swh3 was mapped to a region conserved in Sth1. We show that Swh3 and Sth1 fusion proteins interact in the two-hybrid system and coimmunoprecipitate from yeast cell extracts. We also map interactions between Swh3 and Sth1 and examine the role of a leucine zipper motif in self-association of Swh3. These findings, together with previous analysis of Sth1, indicate that Swh3 and Sth1 are associated in a complex that is functionally distinct from the Swi/Snf complex and essential for viability.

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