Chromosomal localization of the human annexin III (ANX3) gene

The annexins or lipocortins are a new family of calcium-dependent phospholipid-binding proteins. Annexin III has been previously identified as inositol 1,2-cyclic phosphate 2-phosphohydrolase (EC 3.1.4.36), an enzyme of inositol phosphate metabolism, and also as placental anticoagulant protein III, lipocortin III, calcimedin 35-alpha, and an abundant neutrophil cytoplasmic protein. In this study, the gene (ANX3) encoding annexin III was localized to human chromosome 4 at band q21 (q13-q22) by (1) polymerase chain reaction analysis of a human-rodent hybrid cell panel, confirmed by genomic Southern blot analysis of the same panel with a cDNA probe and (2) in situ hybridization with a cDNA probe.     

人αA干扰素在克鲁氏乳酸酵母中的表达和分泌

pE1是由酵母天然质粒pKD1衍生出来的重组穿梭质粒,在克鲁氏乳酸酵母中具有高拷贝,高稳定性等特点。把人αA干扰素分泌表达单元克隆到pE1载体中,得到分泌型表达质粒pE-IFN1。pE-IFN1在克鲁氏乳酸酵母中相当稳定,在非选择性培养基中生长50世代后,大多数酵母细胞仍带有质粒。结果表明,分泌表达单元中的酿酒酵母α因子的分泌信号肽能被克鲁氏乳酸酵母的蛋白质分泌系统所识别,人αA干扰素被分泌到细胞外。在摇瓶培养条件下每升发酵液中含有1—2毫克αA干扰素。     

Genetic relationship between Treponema pallidum and Treponema pertenue, two noncultivable human pathogens.

Genetic relationships among two strains of Treponema pallidum (Nichols and KKJ) and a strain of T. pertenue were determined by measuring the degree of deoxyribonucleic acid sequence homology. The results in indicated that these three virulent, noncultivable treponemes were genetically indistinguishable. Like T. pallidum (Nichols), T. pertenue (Gauthier) had no detectable deoxyribonucleic acid sequence homology with T. phagedenis (biotype Reiter), T. refringens (biotype Noguchi), or with salmon sperm.     

Genetics of Treponema: relationship between Treponema pallidum and five cultivable treponemes.

Three genetically distinct groups of treponemes have been identified by saturation reassociation assays using 125I-labeled treponemal DNAs. The three groups are (i) virulent Treponema pallidum (Nichols strain), (ii) T. phagedenis and its biotypes Reiter and Kazan 5, and (iii) T. refringens biotypes Nichols and Noguchi. There is no detectable DNA sequence homology (less than 5%) among the three groups. The groups have distinct guanine + cytosine contents: 52.4 to 53.7% for T. pallidum, 41.5% for T. refringens, and 38 to 39% for T. phagedenis.     

Novel mutations in ADAMTS13 CUB domains cause abnormal pre-mRNA splicing and defective secretion of ADAMTS13

Hereditary thrombotic thrombocytopenic purpura (TTP) is an autosomal recessive thrombosis disorder, caused by loss-of-function mutations in ADAMTS13. Mutations in the CUB domains of ADAMTS13 are rare, and the exact mechanisms through which these mutations result in the development of TTP have not yet been fully elucidated. In this study, we identified two novel mutations in the CUB domains in a TTP family with an acceptor splice-site mutation (c.3569−1, G>A, intron 25) and a point missense mutation (c.3923, G>A, exon 28), resulting in a glycine to aspartic acid substitution (p.G1308D). In vitro splicing analysis revealed that the intronic mutation resulted in abnormal pre-mRNA splicing, and an in vitro expression assay revealed that the missense mutation significantly impaired ADAMTS13 secretion. Although both the patient and her brother displayed significantly reduced ADAMTS13 activity and increased levels of ultra-large VWF (ULVWF) multimers in plasma, only the female developed acute episodes of TTP. Our findings indicate the importance of the CUB domains for the protein stability and extracellular secretion of ADAMTS13.     

Deficiency of Macf1 in osterix expressing cells decreases bone formation by Bmp2/Smad/Runx2 pathway

Microtubule actin cross‐linking factor 1 (Macf1) is a spectraplakin family member known to regulate cytoskeletal dynamics, cell migration, neuronal growth and cell signal transduction. We previously demonstrated that knockdown of Macf1 inhibited the differentiation of MC3T3‐E1 cell line. However, whether Macf1 could regulate bone formation in vivo is unclear. To study the function and mechanism of Macf1 in bone formation and osteogenic differentiation, we established osteoblast‐specific Osterix (Osx) promoter‐driven Macf1 conditional knockout mice (Macf1^f/fOsx‐Cre). The Macf1^f/fOsx‐Cre mice displayed delayed ossification and decreased bone mass. Morphological and mechanical studies showed deteriorated trabecular microarchitecture and impaired biomechanical strength of femur in Macf1^f/fOsx‐Cre mice. In addition, the differentiation of primary osteoblasts isolated from calvaria was inhibited in Macf1^f/fOsx‐Cre mice. Deficiency of Macf1 in primary osteoblasts inhibited the expression of osteogenic marker genes (Col1, Runx2 and Alp) and the number of mineralized nodules. Furthermore, deficiency of Macf1 attenuated Bmp2/Smad/Runx2 signalling in primary osteoblasts of Macf1^f/fOsx‐Cre mice. Together, these results indicated that Macf1 plays a significant role in bone formation and osteoblast differentiation by regulating Bmp2/Smad/Runx2 pathway, suggesting that Macf1 might be a therapeutic target for bone disease.