Identification and characterization of human Wee1B, a new member of the Wee1 family of Cdk-inhibitory kinases

BACKGROUND: In eukaryotic cells, the kinase activity of the mitosis-promoting complex composed of cyclin B and Cdc2 (Cdk1) is negatively regulated by the phosphorylation of Cdk1 on threonine or tyrosine residues within its ATP binding domain. RESULTS: We identified human Wee1B by searching a sequence database. The predicted human Wee1B protein comprises 561 amino acids. Northern blot analysis revealed that human Wee1B mRNA is particularly abundant in testis. Interestingly, RT-PCR using early embryos revealed that the Wee1B product was readily detectable at the mature oocyte, but abruptly disappeared at embryonic day 2.5, suggesting that the amount of Wee1B mRNA is dependent on the maternal expression. GFP-Wee1B showed a predominantly nuclear localization in HeLa cells. Human Wee1B was able to rescue the lethal phenotype of the fission yeast wee1-50Deltamik1 mutant, and over-expression of the human protein in these cells resulted in cell elongation as a result of arrest of the cell cycle at the G2-M transition. Recombinant Wee1B effectively phosphorylated cyclin B-associated Cdk1 on tyrosine-15, resulting in an inactivation of the kinase activity of Cdk1. CONCLUSION: We identified human Wee1B as a novel Cdk1-inhibitory kinase. The identification of this new member of the Wee1 family suggests that inhibition of Cdk1 is mediated at multiple levels in mammals.     

Complete genome sequence of Tunisvirus,a new member of the proposed family Marseilleviridae

Marseillevirus is the founding member of the proposed family Marseilleviridae, which is the second discovered family of giant viruses that infect amoebae. These viruses have been recovered from environmental water samples and, more recently, from humans. Tunisvirus was isolated from fountain water in Tunis, Tunisia, by culturing on Acanthamoeba spp. and is a new marseillevirus. We describe here its 380,011 base-pair genome. A total of 484 proteins were identified, among which 320 and 358 have an ortholog in Marseillevirus and Lausannevirus (e-value <1e-2), respectively, and 259 and 299 have best reciprocal hits with a Marseillevirus and a Lausannevirus protein, respectively. In addition, a significant hit was found in organisms other than marseilleviruses for 144 Tunisvirus proteins, indicating extensive lateral gene transfers, as has been demonstrated previously for Marseillevirus. Finally, a total of 21 ORFans were identified. Phylogeny reconstructions and analysis of the gene repertoires of marseilleviruses, including the proportion of orthologs and the mean amino acid identity between genes in pairs, suggest that the proposed family Marseilleviridae encompasses three lineages. Lineage A is composed of Marseillevirus, Cannes 8 virus and Senegalvirus; lineage B is represented by Lausannevirus alone; and lineage C has Tunisvirus as its first member. Taken together, these findings suggest that the marseilleviruses display a substantial level of diversity.     

S-s-U-phenotype in a Caucasian family

The S-s-U-blood group phenotype, commonly detected in Black populations, was found in a Caucasian family in which 4 homozygous U-negative members exhibit this phenotype. The erythrocyte blood group antigens and membrane glycoproteins from these donors have been serologically and electrophoretically characterized and compared to the U-negative red cells from Black people. Caucasian and Black S-s-U-red blood cells behaved identically since both lack Ss and U antigens and the minor red-cell membrane glycophorin B.     

Sensenbrenner syndrome: a new member of the hepatorenal fibrocystic family

Cranioectodermal dysplasia (CED, Sensenbrenner syndrome; OMIM #218330) is an autosomal recessive disorder reported only in 15 cases, which is characterized by dolichocephaly, rhizomelic dwarfism, dental and nail dysplasia, and progressive tubulo-interstitial nephritis (TIN) leading to end-stage renal failure. Herein, we describe a new patient with cranio-ectodermal dysplasia. Unlike previously reported cases, this 4-year-old child presented with tubulo-interstitial nephropathy associated with liver cystic disease and elevated liver enzymes. The liver biopsy demonstrated congenital hepatic fibrosis secondary to ductal plate malformation. The coexistence of a chronic tubulo-interstitial renal disease with lesions associated to malformations of the hepatic ductal plate indicates that CED as a new member of the congenital hepatorenal fibrocystic syndromes.     

Characterization of a new HLA-B39 allele, B*3913, in a Brazilian Caucasian

Abstract: A panel of samples, previously typed by serology, was retyped using a line probe assay. One sample from a Brazilian Caucasian individual was serologically typed as B52/B39, but showed an aberrant HLA-B pattern on the diagnostic strip and was typed as B*52012/B*39new. Further analysis by allele-specific amplification and subsequent sequencing of ex-ons 2 and 3 revealed a G(B*3908)-to-T nucleotide substitution at position 467 (codon 156) resulting in an Arg (B*3908)-to-Leu substitution. Furthermore, the sequence revealed a silent mutation at position 174 (codon 58): a G(B*3908)-to-A nucleotide switch. The sequence has been sent to the EMBL databank and the HLA Nomenclature Committee, and the allele was named B*3913.     

B7S1, a novel B7 family member that negatively regulates T cell activation

T cell activation by antigen-presenting cells (APC) is regulated by positive and negative costimulatory molecules in the B7 family. Here we describe a novel addition in this family, designated as B7S1, which is uniquely anchored to the cell membrane via a GPI linkage. B7S1 is expressed on professional APC and widely distributed in nonlymphoid tissues. A soluble B7S1-Ig fusion protein binds to activated but not naive T cells. B7S1-Ig inhibits T cell activation and IL-2 production. A monoclonal antibody that blocks binding of B7S1 to its receptor enhances T cell proliferation in vitro and exacerbates experimental autoimmune encephalomyelitis in vivo. This study identifies a novel negative regulator of T cell activation and further reveals complex costimulatory regulation of immune responses.     

Identification of a new HLA-B*78 allele in a Hispanic family

A new B*78 variant, B*7804, was detected in three members of a Hispanic family. The novel B*78 sequence differs from B*78021 by two substitutions: T at nucleotide 527 (all other B*78s have A) and T at nucleotide 583 (all other B*78s have a C). Both nucleotide substitutions encode amino acid changes at codons 152 and 171, respectively.     

B7家族新成员HHLA2在人类恶性肿瘤中的研究现状

HHLA2(human endogenous retrovirus-H long terminal repeat-associating 2)是第二信号分子B7家族的一个新成员,与不同的受体结合提供T细胞活化的共抑制或共刺激信号.研究表明,HHLA2很少表达于人类正常组织,却高表达于多种人类恶性肿瘤组织,提示HHLA2可能参与免疫逃逸,对恶性肿瘤的发生、发展、转移及预后有一定影响,可能是恶性肿瘤免疫治疗的一个新靶点.因而,深入研究H H L A 2在多种恶性肿瘤中的表达情况有重要意义.     

BTLA, a new inhibitory B7 family receptor with a TNFR family ligand

B and T lymphocyte attenuator （BTLA）, identified as an immune inhibitory receptor recently, plays widespread roles on T and B cells. Emerging evidence has generated plentiful information on the mechanisms which BTLA mediates negative regulation in immune responses and involves in a variety of physiological and pathological processes. The exploration of the biological mechanisms and regulation of BTLA will open possibilities on novel therapeutic strategies in immune-related diseases. Cellular ＆ Molecular Immunology. 2005;2（6）：427-432.     

Identification of a novel human DDX40gene,a new member of the DEAH-box protein family

The DExH/D-box superfamily of RNA helicases seems to play key roles during RNA metabolism, such as pre-mRNA splicing, ribosome biogenesis, and others. We have cloned a new gene of the DEAH-box protein subgroup, designated DDX40 (DEAD/H-box polypeptide 40 gene). DDX40 contains 3656 nucleotides and codes for a putative 779-amino-acid protein. Sequence analysis of the cDNA product revealed that it contained a DEAH (Asp-Glu-Ala-His) sequence motif and other conserved motifs. The DDX40 protein shared 53% and 43% amino acid identity with human DDX8 and yeast Drh1, respectively, in the conserved region. Northern blot analysis showed that DDX40 was expressed ubiquitously in the eight tissues examined, implying a general physiological function of the protein. We speculate that, like other members of the DExH/D-box superfamily, DDX40 may play roles in pre-mRNA splicing, ribosome biogenesis and other RNA processing functions.     

Identification of a novel human DDX40 gene, a new member of the DEAH-box protein family

 The DExH/D-box superfamily of RNA helicases seems to play key roles during RNA metabolism, such as pre-mRNA splicing, ribosome biogenesis, and others. We have cloned a new gene of the DEAH-box protein subgroup, designated DDX40 (DEAD/H-box polypeptide 40 gene). DDX40 contains 3656 nucleotides and codes for a putative 779-amino-acid protein. Sequence analysis of the cDNA product revealed that it contained a DEAH (Asp-Glu-Ala-His) sequence motif and other conserved motifs. The DDX40 protein shared 53% and 43% amino acid identity with human DDX8 and yeast Drh1, respectively, in the conserved region. Northern blot analysis showed that DDX40 was expressed ubiquitously in the eight tissues examined, implying a general physiological function of the protein. We speculate that, like other members of the DExH/D-box superfamily, DDX40 may play roles in pre-mRNA splicing, ribosome biogenesis and other RNA processing functions. Received: August 7, 2002 / Accepted: September 12, 2002     

Rwdd1, a thymus aging related molecule, is a new member of the intrinsically unstructured protein family

We had previously identified a novel protein termed Rwddl whose expression in thymus is decreased in aged or oxidatively stressed mice. In the present study, we found that Rwddl expressed in both prokaryotic and eukaryotic ceils showed a slower migration rate on SDS-PAGE gel. In addition, Rwddl was more sensitive to proteinase proteolysis. Furthermore, being a highly acidic protein which contains an RWD domain, Rwddl shared a high level of sequence similarity with Gir2, a member of the intrinsically unstructured protein （IUP）. These findings suggest that Rwddl is a novel member of the IUP family.     

Complete nucleotide sequence of rose yellow leaf virus,a new member of the family Tombusviridae

The genome of the rose yellow leaf virus (RYLV) has been determined to be 3918 nucleotides long and to contain seven open reading frames (ORFs). ORF1 encodes a 27-kDa peptide (p27). ORF2 shares a common start codon with ORF1 and continues through the amber stop codon of p27 to encode an 87-kDa (p87) protein that has amino acid similarity to the RNA-dependent RNA polymerase (RdRp) of members of the family Tombusviridae. ORFs 3 and 4 have no significant amino acid similarity to known functional viral ORFs. ORF5 encodes a 6-kDa (p6) protein that has similarity to movement proteins of members of the Tombusviridae. ORF5A has no conventional start codon and overlaps with p6. A putative +1 frameshift mechanism allows p6 translation to continue through the stop codon and results in a 12-kDa protein that has high homology to the carmovirus p13 movement protein. The 37-kDa protein encoded by ORF6 has amino acid sequence similarity to coat proteins (CP) of members of the Tombusviridae. ORF7 has no significant amino acid similarity to known viral ORFs. Phylogenetic analysis of the RdRp amino acid sequences grouped RYLV together with the unclassified Rosa rugosa leaf distortion virus (RrLDV), pelargonium line pattern virus (PLPV), and pelargonium chlorotic ring pattern virus (PCRPV) in a distinct subgroup of the family Tombusviridae.     

Complete nucleotide sequence of the temperate bacteriophage LBR48, a new member of the family Myoviridae

The complete genomic sequence of LBR48, a temperate bacteriophage induced from a lysogenic strain of Lactobacillus brevis, was found to be 48,211 nucleotides long and to contain 90 putative open reading frames. Based on structural characteristics obtained from microscopic analysis and nucleic acid sequence determination, phage LBR48 can be classified as a member of the family Myoviridae. Analysis of the genome showed the conserved gene order of previously reported phages of the family Siphoviridae from lactic acid bacteria, despite low nucleotide sequence similarity. Analysis of the attachment sites revealed 15-nucleotide-long core sequences.     

PAT1, a new member of the GRAS family, is involved in phytochrome A signal transduction

Light signaling via the phytochrome A (phyA) photoreceptor controls basic plant developmental processes including de-etiolation and hypocotyl elongation. We have identified a new Arabidopsis mutant, pat (phytochrome A signal transduction)1-1, which shows strongly reduced responses in continuous far-red light. Physiological and molecular data indicate that this mutant is disrupted at an early step of phyA signal transduction. The PAT1 gene encodes a cytoplasmic protein of 490 amino acids with sequence homologies to the plant-specific GRAS regulatory protein family. In the pat1-1 mutant, a T-DNA insertion introduces a premature stop codon, which likely results in the production of a truncated PAT1 protein of 341 amino acids. The semidominant phenotype of this mutant can be recapitulated by overexpression of an appropriately truncated PAT1 gene in the wild type. The results indicate that the truncated PAT1 protein acts in a dominant-negative fashion to inhibit phyA signaling.