Taxonomic distribution of proteins containing CXC domains

The tree below includes only several representative species and genera. The complete taxonomic breakdown of all proteins containing CXC domains can be accessed here. Click the counts or percentage values to display the corresponding proteins.

TSO1 is a novel protein that modulates cytokinesis and cell expansion inArabidopsis.

Hauser BA, He JQ, Park SO, Gasser CS
Development. 2000; 127: 2219-26

Previous analyses of tso1 mutants revealed a loss of control of directionalcellular expansion and coordination of growth of adjacent cells, and defects inkaryokinesis and cytokinesis. We isolated TSO1 using a map-based approach, andshow that it is a member of a family of at least three genes in Arabidopsis.Consistent with the mutant phenotype, TSO1 transcript was most abundant inflowers, where it accumulated to the highest levels in developing ovules andmicrospores. The putative TSO1 protein has two cysteine-rich regions that aresimilar to the CXC domains of a variety of proteins from plants and animals,including a class of kinesins involved in chromosome segregation, and enhancer ofzeste-type proteins. Visualization of TSO1-fusion proteins indicated that TSO1 isa nuclear protein. The tso1 mutant phenotypes and the novelty of the TSO1sequence suggest the existence of previously unknown participants in regulationof directional processes in eukaryotic cells.

A novel testis-specific metallothionein-like protein, tesmin, is an early marker of male germ cell differentiation.

Sugihara T, Wadhwa R, Kaul SC, Mitsui Y
Genomics. 1999; 57: 130-6

We have cloned a novel cDNA encoding testis-specific metallothionein-likeprotein, tesmin, by randomized RT-PCR on RNA from mouse tissues. Twotesmin-related transcripts (2.2 and 1.8 kb) in mouse and one (2.1 kb) in humanwere detected and cloned. These encode a cysteine-rich 32-kDa protein thatcontained a metallothionein-like motif. In situ hybridization analysis in adultmouse testis showed that tesmin is specifically expressed in spermatocytes.Quantitative RT-PCR at different stages of mouse postnatal development (days 4,8, 12, 18, and 42) revealed that tesmin is expressed as early as day 8 andcoincides with the entry of germ cells into meiosis. Furthermore, adult W/Wvsterile mice that harbor the c-kit mutation lacked tesmin expression. The gene isassigned to mouse chromosome 19B, which has been reported to translocate (11;19) in male sterile mice.

Characterization of the cyn operon in Escherichia coli K12.

Sung YC, Fuchs JA
J Biol Chem. 1988; 263: 14769-75

Escherichia coli can overcome the toxicity of environmental cyanate by hydrolysisof cyanate to ammonia and bicarbonate. This reaction is catalyzed by the enzymecyanase, encoded by the cynS gene. The nucleotide sequence of cynS has beenreported (Sung, Y.-c., Anderson, P. M., and Fuchs, J. A. (1987) J. Bacteriol.169, 5224-5230). The nucleotide sequence of the complete cyn operon has now been determined. The cyn operon is approximately 2600 base pairs and includes cynT,cynS, and cynX, which encode cyanate permease, cyanase, and a protein of unknown function, respectively. Two cyanate-inducible transcripts of 1500 and 2500nucleotides, respectively, were detected by Northern blot analysis. S1 nucleasemapping experiments indicated that two different cyn mRNAs have a common 5'-endand two different 3'-ends. One 3'-end was located within the coding region ofcynX, whereas the other 3'-end includes the entire DNA sequence of cynX. Thelonger transcript contained 98 nucleotides complementary to lac mRNA produced by the predominant lac transcription termination sequence. Termination vectors were used to show that both 3'-ends were generated by sequences that causedtranscriptional termination in vivo. Expression vectors were used to demonstrate that a protein corresponding to the expected size was synthesized from the DNAfragment containing the open reading frame designated cynX. The predicted aminoacid sequence of cynX indicates that it is a very hydrophobic protein. The level of cynX expression was significantly less than that of cynT or cynS expression.