ISSN:0265-9247    

DOI:10.1002/bies.950160602

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

ISSN:0265-9247    

DOI:10.1002/bies.950160603

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

ISSN:0265-9247    

DOI:10.1002/bies.950160604

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

ISSN:0265-9247    

DOI:10.1002/bies.950160605

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

ISSN:0265-9247    

DOI:10.1002/bies.950160606

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThe link between oncogenesis and normal development is well illustrated by the study of the Wnt family of proteins. The firstWntgene (int‐1) was identified over a decade ago as a proto‐oncogene, activated in response to proviral insertion of a mouse mammary tumor virus. Subsequently, the discovery thatDrosophila wingless, a developmentally important gene, is homologous toint‐1supported the notion thatint‐1may have a role in normal development. In the last few years it has been recognized that int‐1 and Wingless belong to a large family of related glyco‐proteins found in vertebrates and invertebrates. In recognition of this, members of this family have been renamed Wnts, an amalgam of int and Wingless. Investigation ofWntgenes inXenopusand mouse indicates that Wnts have a role in cell proliferation, differentiation and body axis formation. Further analysis inDrosophilahas revealed that Wingless function is required in several developmental processes in the embryo and imaginal discs. In addition, a genetic approach has identified some of the molecules required for the transmission and reception of the Wingless signal. We will review recent data which have contributed to our growing understanding of the function and mechanism ofDrosophilaWingless signaling in cell fate determination, growth and specification

ISSN:0265-9247    

DOI:10.1002/bies.950160607

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThe molecular cloning of new neuroactive growth factors and their receptors has greatly enhanced our understanding of important interactions among receptors and singnaling molecules. These studies have begun to illuminate some of the mechanisms that allow for specificity in neuronal signaling. Model cell systems, such as the PC‐12 pheochromocytoma cell line, express receptors for these different neurotirophic factors, leading to comparisons of signaling pathways for these factors. Upon binding their ligands, these receptors undergo phosphorylation on tyrosine residues, which directs their interaction with signaling proteins containing src homology (SH2) domains, sequences that mediate associations with tyrosine‐phosphorylated proteins. These SH2 proteins translate the tyrosine kinase activity of receptors into downstream events that result in the specific cellular response. Investigations such as these have revealed that molecular specificity in signaling pathways may arise from combinatorial diversity in interactions between receptors and key regulatory prote

ISSN:0265-9247    

DOI:10.1002/bies.950160608

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThe elongated fiber cells of the eye lens contain a unique cytoskeletal system, the beaded chain filaments (BFs). The BFs had been morphologically identified more than two decades ago, but the precise identity of their subunit molecules remained unknown. Recently, use of recombinant DNA approaches, refined morphological and immunochemical studies and experiments with mutant mice have allowed the molecular dissection of these structures and provided clues about their potential functins. The BFs represent a highly specialized network of intermediate filaments (IFs) juxtaposed to the plasma membrane. They are obligate heteropolymers composed of two lens‐specific polypeptides, filensin and phakinin. In this review we discuss the properties, molecular interactions andin situarrangement of these two proteins, and comment on their potential roles during lens developmen

ISSN:0265-9247    

DOI:10.1002/bies.950160609

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractInsect and crustacean lineages diverged over 500 Myr ago, and there are continuing uncertaintles about whether they evolved from a common arthropod ancestor or, alternatively, they evolved independently from annelid worms. Despite the diversity of their limbs and lifestyles, the nervous systems of insects and crustaeeans share many common features both in development and in function. Cellular and molecular embryology techniques reveal good evidence for homologies in the developing segmental ganglia. In the visual system, this seemingly common programme of insect and crustacean CNS development culminates in common adult neural function. Comparisons of the cellular anatomy and physiology of animals as diverse as flies and crayfishes indicate that the neural circuits in the lamina of their optic lobe have been inherited largely unchanged from a common ancestor with good compound eyes.

ISSN:0265-9247    

DOI:10.1002/bies.950160610

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractCurrent models for RNA synthesis involve an RNA polymerase that tracks along a static template. However, research on chromatin loops suggests that the template slides past a stationary polymerase; individual polymerases tie the chromatin fibre into loops and clusters of polymerases determine the basic structure of the interphase and metaphase chromosome. RNA polymerase is then both a player and a manager of the chromosome loop.

ISSN:0265-9247    

DOI:10.1002/bies.950160611

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY