FPA, a gene involved in floral induction in Arabidopsis, encodes a protein containing RNA-recognition motifs

FPA is a gene that regulates flowering time in Arabidopsis via a pathway that is independent of daylength (the autonomous pathway). Mutations in FPA result in extremely delayed flowering. FPA was identified by means of positional cloning. The predicted FPA protein contains three RNA recognition motifs in the N-terminal region. FPA is expressed most strongly in developing tissues, similar to the expression of FCA and LUMINIDEPENDENS, two components of the autonomous pathway previously identified. Overexpression of FPA in Arabidopsis causes early flowering in noninductive short days and creates plants that exhibit a more day-neutral flowering behavior.     

Isolation of a yeast gene involved in species-specific pre-tRNA processing.

To identify genes involved in pre-tRNA processing, we searched for yeast DNA sequences that specifically enhanced the expression of the SUP4(G37) gene. The SUP4(G37) gene possesses a point mutation at position 37 of suppressor tRNA(Tyr). This lesion results in a reduced rate of pre-tRNA splicing and a decreased level of nonsense suppression. A SUP4(G37) strain was transformed with a yeast genomic library, and the transformants were screened for increased suppressor activity. One transformant contained a plasmid that encoded an unessential gene, STP1, that in multiple copies enhanced the suppression of SUP4(G37) and caused increased production of mature SUP4(G37) product. Disruption of the genomic copy of STP1 resulted in a reduced efficiency of SUP4-mediated suppression and the accumulation of pre-tRNAs. Not all intron-containing pre-tRNAs were affected by the stp1-disruption. At least five of the nine families of pre-tRNAs were affected. Two other species, pre-tRNA(Ile) and pre-tRNA(3Leu), were not. We propose that STP1 encodes a tRNA species-specific product that functions as a helper for pre-tRNA splicing. The STP1 product may interact with pre-tRNAs to generate a structure that is efficiently recognized by splicing machinery.     

The murine Pes1 gene encodes a nuclear protein containing a BRCT domain

Pescadillo was originally identified in the zebrafish Danio rerio as a site of a retrovirus-insertion mutation that caused severe defects during embryogenesis. In particular, growth of the fetal zebrafish liver was significantly affected by loss of pescadillo function. To begin to understand the role of pescadillo during mammalian hepatogenesis we identified the murine homologue of pescadillo and named it Pes1. A single gene localized to chromosome 11 on the mouse genome encodes Pes1. Although Pes1 mRNA was detected in all tissues examined it was present at the highest levels in both adult and fetal liver. Analysis of the predicted amino acid sequence of Pes1 found it to contain a BRCT domain, which has previously been found in several proteins involved in cell-cycle checkpoints and DNA repair. Consistent with a putative role in these processes we found that when recombinant Pes1 protein was expressed in HepG2 cells it localized to the nucleus.     

Cloning and characterization of the CDZFP gene which encodes a putative zinc finger protein.

We report here the cloning and characterization of a novel human cytoplasm-distribution zinc finger protein (CDZFP) gene, isolated from human ovary cDNA library, and mapped to 4p12 by searching the UCSC genomic database. The CDZFP cDNA is 1793 base pairs in length and contains an open reading frame (ORF) encoding 236 amino acids. The CDZFP gene consists of 7 exons and encodes a putative zinc finger protein with a transmembrane region and two zinc finger motifs. Subcellular localization demonstrated that CDZFP protein was located in the cytoplasm when overexpressed in Hela cells and northern blot analysis revealed that CDZFP was ubiquitously expressed in 16 human tissues.     

The gene teashirt is required for the development of Drosophila embryonic trunk segments and encodes a protein with widely spaced zinc finger motifs.

We have discovered a reporter gene insertion that is expressed in the trunk region of Drosophila embryos. Genetic and molecular details of a new regulatory gene neighboring the reporter gene insertion, which we call teashirt (tsh), are described. In situ hybridization of a tsh probe to embryos shows that this gene is expressed in a way similar to the reporter gene. Mutations of tsh show that the gene is required for normal development of the ventral trunk region of embryos, which correlates with the spatial expression of the gene in the anteroposterior axis but not in the dorsoventral axis. Sequencing of a tsh cDNA shows that the putative protein possesses three distantly spaced CX2CX12HX5H zinc finger motifs.     

JAZ requires the double-stranded RNA-binding zinc finger motifs for nuclear localization.

We have cloned and characterized a novel zinc finger protein, termed JAZ. JAZ contains four C(2)H(2)-type zinc finger motifs that are connected by long (28-38) amino acid linker sequences. JAZ is expressed in all tissues tested and localizes in the nucleus, primarily the nucleolus. JAZ preferentially binds to double-stranded (ds) RNA or RNA/DNA hybrids rather than DNA. Mutation of individual zinc finger motifs reveals that the zinc finger domains are not only essential for dsRNA binding but are also required for its nucleolar localization, which demonstrates a complex trafficking mechanism dependent on the nucleic acid-binding capability of the protein. Furthermore, forced expression of JAZ potently induces apoptosis in murine fibroblast cells. Thus, JAZ may belong to a class of zinc finger proteins that features dsRNA binding and may regulate cell growth via the unique dsRNA binding properties.     

The Drosophila gene escargot encodes a zinc finger motif found in snail-related genes.

Two independent P-element enhancer detection lines were obtained that express lacZ in a pattern of longitudinal stripes early in germband elongation. In this paper, molecular and genetic characterization of a gene located near these transposons is presented. Sequence analysis of a cDNA clone from the region reveals that this gene has a high degree of similarity with the Drosophila snail gene (Boulay et al., 1987). The sequence similarity extends over 400 nucleotides, and includes a region encoding five tandem zinc finger motifs (72% nucleotide identity; 76% amino acid identity). This region is also conserved in the snail homologue from Xenopus laevis (76% nucleotide identity; 83% amino acid identity) (Sargent and Bennett, 1990). We have named the Drosophila snail-related gene escargot (esg), and the region of sequence conservation common to all three genes the 'snailbox'. A number of Drosophila genomic DNA fragments cross-hybridize to a probe from the snailbox region suggesting that snail and escargot are members of a multigene family. The expression pattern of escargot is dynamic and complex. Early in germband elongation, escargot RNA is expressed in a pattern of longitudinal stripes identical to the one observed in the two enhancer detection lines. Later in development, escargot is expressed in cells that will form the larval imaginal tissues, escargot is allelic with l(2)35Ce, an essential gene located near snail in the genome.