{"id":954,"date":"2007-05-04T18:37:02","date_gmt":"2007-05-04T17:37:02","guid":{"rendered":"http:\/\/www.wjst.de\/blog\/2007\/05\/04\/where-do-i-come-from-where-will-i-go\/"},"modified":"2007-05-04T18:40:48","modified_gmt":"2007-05-04T17:40:48","slug":"where-do-i-come-from-where-will-i-go","status":"publish","type":"post","link":"https:\/\/www.wjst.de\/blog\/sciencesurf\/2007\/05\/where-do-i-come-from-where-will-i-go\/","title":{"rendered":"Where do I come from, where will I go"},"content":{"rendered":"<p>The <a href=\"https:\/\/www.wjst.de\/blog\/2007\/01\/12\/a-longe-fuse\/\">fate of an individual cell<\/a> in the human body is a mystery. A new Nature paper now provides a follow up of single cells of the epithelial cell layer. It is certainly a paper that will rank among the top 10 this year,<!--more--> although I have difficulties in understanding the setup. To track the cells, the authors use endogenous flurorescent staining that can be switched on by injecting multiple doses of tamoxifen.<\/p>\n<blockquote><p>\nAnimals transgenic for the tamoxifen-regulated mutant of cre recombinase (AhcreERT), expressed from the inducible CYP1A1 promoter, were crossed onto the R26EYFP\/EYFP reporter strain, in which a conditional allele of enhanced yellow fluorescent protein (EYFP) is targeted to the Rosa26 locus (Supplementary Fig. S1a; refs 16, 17). In the resultant AhcreERT R26EYFP\/wt heterozygotes, EYFP is expressed in a dose-dependent manner following transient expression of cre induced by a treatment with betaNF and tamoxifen at 6\u00e2\u20ac\u201c9 weeks of age.\n<\/p><\/blockquote>\n<p>I am not quite sure where the experiment is starting off. Later on in this paper the authors write about &#8220;stem cells&#8221; while the title is about &#8220;progenitors&#8221; which may be a huge difference.<br \/>\nI also do not understand why these colored cells appear only in a frequency of 1 to 600  as 8% at a given time point may be dividing &#8220;progenitors&#8221; according to Fig. 4B.<br \/>\nThe authors challenge the current <em>stem cell \/ transit amplifying<\/em> hypothesis where the basal layer clone needs to be a time-independent proliferative unit.<\/p>\n<blockquote><p>\nFaced with this apparent contradiction, one could attempt to revise the stem cell\/TA cell model, but staying within the general paradigm. This might include introducing the capacity for stem-cell ageing and\/or migration. Alternatively, one could try to exploit the range of experimental data to seek evidence for a new paradigm [&#8230;] Here we argue that the clone fate data are compatible with a model in which IFE [interfollicular epidermis] is maintained by only one compartment of proliferating cells.\n<\/p><\/blockquote>\n<p>Why is stem cell ageing not an equal likely explanation? Getting more insight where <a href=\"https:\/\/www.wjst.de\/blog\/2007\/02\/13\/ab-initio-creata-sum\/\">cells come from<\/a> and where they go, remains a fascinating challenge.<br \/>\n<em><a href=\"http:\/\/www.nature.com\/nature\/journal\/v446\/n7132\/abs\/nature05574.htm\">scienceblog:doi:10.1038\/nature05574<\/a><\/em><\/p>\n<p><a href=\"https:\/\/www.wjst.de\/blog\/wp-content\/uploads\/2007\/05\/wheredowego.png\" title='' data-rel=\"key-image-0\" data-rl_title=\"\" data-rl_caption=\"\"><img src='https:\/\/www.wjst.de\/blog\/wp-content\/uploads\/2007\/05\/wheredowego.png' alt='wheredowego.png' \/><\/a><\/p>\n\n<p>&nbsp;<\/p>\n<div class=\"bottom-note\">\n  <span class=\"mod1\">CC-BY-NC Science Surf , accessed 07.04.2026<\/span>\n <\/div>","protected":false},"excerpt":{"rendered":"<p>The fate of an individual cell in the human body is a mystery. A new Nature paper now provides a follow up of single cells of the epithelial cell layer. It is certainly a paper that will rank among the top 10 this year, &nbsp; CC-BY-NC Science Surf , accessed 07.04.2026<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[],"class_list":["post-954","post","type-post","status-publish","format-standard","hentry","category-genetics-biology"],"_links":{"self":[{"href":"https:\/\/www.wjst.de\/blog\/wp-json\/wp\/v2\/posts\/954","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.wjst.de\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.wjst.de\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.wjst.de\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.wjst.de\/blog\/wp-json\/wp\/v2\/comments?post=954"}],"version-history":[{"count":0,"href":"https:\/\/www.wjst.de\/blog\/wp-json\/wp\/v2\/posts\/954\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.wjst.de\/blog\/wp-json\/wp\/v2\/media?parent=954"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.wjst.de\/blog\/wp-json\/wp\/v2\/categories?post=954"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.wjst.de\/blog\/wp-json\/wp\/v2\/tags?post=954"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}