Polarized cell movements are essential to the cell rearrangements that occur during morphogenesis. In Xenopus, cell polarity is reflected in the directional cell intercalations that drive the morphogenetic movements characterizing gastrulation. While these cell behaviours are well described, the molecular mechanism underlying this cell polarity is unknown. PAR-3 is a multi-domain scaffolding protein and a key regulator of cell polarity. I have isolated a cDNA encoding Xenopus PAR-3 and generated several mutant constructs, each lacking a conserved domain. Initial characterization of GFP-tagged PAR-3 in A6 cells demonstrates localization to points of cell-cell contact in epithelial sheets, as well as at the leading edge of migrating cells. PAR-3 constructs lacking the CR1 or PDZ1 domain fail to compartmentalize properly and are found in the cytoplasm. Eliminating the PDZ3 domain resulted in a loss of contact inhibition. Mutation of the aPKC phosphorylation site created a membrane hyper-accumulation phenotype. Together these data suggest that the CR1 and PDZ1 domains mediate membrane compartmentalization that is modulated through aPKC phosphorylation, while the PDZ3 domain is required for contact inhibition. In embryos, PAR-3 is expressed throughout gastrulation and over-expression of PAR-3 inhibits blastopore closure indicating a requirement during gastrulation. Inhibition is relieved when the construct lacking the CR1 domain is over-expressed. PAR-3 was localized to the cell periphery in axial mesoderm. Localization was abolished with deletion of the CR1 domain indicating that membrane targeting of PAR-3 is required for gastrulation and this targeting is dependent on oligomerization of PAR-3. This investigation also suggests PAR-3 functions independent of the PAR complex in Xenopus embryos indicating involvement of a different PAR-3 signaling pathway.

Masteroppgaven har følgende problemstilling: Hvordan oppleves det for et par å bli foreldre for første gang, og i hvilken grad vil erfaringer fra deres egen barndom være med på å påvirke deres forventninger? Målet med studien har vært å undersøke hva slags tanker, følelser, erfaringer og opplevelser som tre par vil sitte igjen med etter å ha opplevd overgangen fra å være i et parforhold til å bli en familie. Studien bygger på den kvalitative forskningsmetoden, og benytter intervju som datainnsamlingsstrategi. Masteroppgaven har et fenomenologisk perspektiv, og det har blitt gjennomført tre halvstrukturerte intervjuer med hvert av parene som har deltatt i denne studien. Det teoretiske rammeverket består blant annet av Alfred Adlers begreper om konstruerte mål og privat logikk, samt John Bowlby sin teori om tilknytning, som har blitt benyttet for å kunne belyse hvordan et par sin oppfattelse av det å bli foreldre i en viss grad kan stamme fra deres egen barndom. Patricia Noller og Judith Feeney sin videreutvikling av Bowlby sin teori har også blitt belyst, i tillegg til Carolyn P. Cowan og Philip A. Cowan sitt teoretiske arbeid om hvordan det oppleves for par å bli foreldre for første gang. Analyseringen av den innsamlede dataen fra intervjuene har vist at datamaterialet kan bli delt inn i tre hovedkategorier. 1) Vi som par, tar for seg parets tidligere erfaringer fra å være i en familie, samt deres forventinger til det å selv bli foreldre. 2) Barnet melder sin ankomst – hvem er du, og hvem er vi nå?, omhandler førsteinntrykket til de nybakte foreldrene, det å bli kjent med sitt eget barn og seg selv som foreldre, hvordan paret velger å benytte erfaringene de allerede har fra det å være i en familie og hvordan forventingene til seg selv og sin partner har endret seg etter fødselen. 3) Vi som familie, tar for seg hvordan paret føler at det er å være i et parforhold i en familie og hvilke forventninger de har nå og videre inn i fremtiden. Resultatene fra studien har vist at en av de viktigste forutsetningene for hvordan to mennesker i et parforhold vil oppleve det å bli foreldre bygger på hvordan paret hadde det før barnet ble født. Har paret et lykkelig og tilfredsstillende forhold før de bestemmer seg for å danne en familie, er sannsynligheten større for at de også etter fødselen av deres barn vil være lykkelige sammen. En annen viktig forutsetning er hvordan paret håndterer vanskelige og utfordrende situasjoner. Har paret effektive og konstruktive måter å løse et problem på, er det også sannsynlig at de vil trives bedre som foreldre sammen, enn parene som ikke har gode måter å løse uenigheter på. Videre tar studien også for seg hvordan parenes barndom og forhold til sine egne foreldre kan påvirke deres tanker og følelser rundt det å selv bli foreldre. Et annet viktig punkt innenfor denne vinklingen er hvordan den enkelte foreldre selv tenker om sin barndom, og hvorvidt vedkommende ønsker å følge sine foreldres fotspor i oppdragelsen av sitt barn, eller om de ønsker å gi sitt barn en annen start på livet enn de selv hadde. / The aim of this qualitative study was to find out how three couples experienced the shift from being in a relationship to becoming a family. The problem to be addressed is: How does it feel for a couple to become parents for the first time, and to what extent will the experiences of their own childhood influence their expectations? The research methodology approach is anchored in a phenomenological perspective and semi-structured in-dept interveiws were made. Each couple was interviewed together, making three interviews the basis of this study. The theory presented in this study includes Alfred Alders and his theory about fictional goals and private logic. John Bowlbys attachment theory will also be discussed, to bring some understandig about how the thoughts and feelings to the freshly parents can be traced back to their own childhood. Patricia Noll and Judith Feeney's development of Bowlby's theory will also be discussed, in addition to Carolyn P. Cowan and Philip A. Cowan's theoretical work on how it is perceived for couples to become parents for the first time. The analysis of the collected data from the interviews have shown that the data can be divided into three main categories. 1) We as a couple, deals with the couple's previous experience from being in a family, and their expectations for becoming a parent. 2) The child enters the scene - who are you, and who are we now?, deals with the first impression of the freshly parents, getting to know their children and themselves as parents, how the couple choose to use the experience they already have from the being in a family and how expectations of themselves and their partner has changed since the birth of their child. 3) We as a family, discusses how the couple feel it is to be in a relationship in a family and what expectations they have now and into the future. The study results have shown that one of the most important aspects of how two people in a relationship will find it to be parents, is based on how the couple had it before their child was born. If the couple had a happy and satisfying relationship before they decide to form a family, chances are that they are also after the birth of their children will be happy together. Another important factor is how the couple handles difficult and challenging situations. If the couple have effective and constructive ways to solve a problem, will it also be likely that they will thrive better as parents together than couples who do not have good ways to resolve disagreements on. Further study will also examine how couples childhood and relationship with their own parents can influence their thoughts and feelings about becoming parents themselves. Another important point is how the parents think about their own childhood, and whether they wish to follow in their parents' footsteps in the upbringing of their child, or whether they want to give their child a different start in life than they had.

Extr. de: Diss.--Physique--Stuttgart (Allemagne)--Université de Stuttgart, 2002. / Thèse rédigée en anglais avec un résumé en allemand. Bibliogr. p. 245-266.

Proefschrift--Universiteit Leiden, 2004. / Notes bibliogr.

Avhandling--Linköping, 2000. / Résumé en anglais. Bibliogr. p. 181-190.

Texte remanié de: Diss.--Berlin, 1999. / Bibliogr. p. 266-293. Notes bibliogr. Index.

Diss.--Kiel Universität, 2001. / Bibliogr. p. 173-179.

Thèse doctorat : Génie Civil : Villeurbanne, INSA : 2002. / Titre provenant de l'écran-titre. Bibliogr. p. 289-299.

Reproduction de : Thèse de doctorat : Informatique de l'image et du langage : Toulouse, INPT : 2005. / Titre provenant de l'écran-titre. Bibliogr. 261 réf.

Thèse doctorat : Mécanique : La Rochelle : 2005. / Bibliogr. p. 245-255.