{"id":369,"date":"2014-06-25T20:26:52","date_gmt":"2014-06-25T20:26:52","guid":{"rendered":"https:\/\/lipsick.su.domains\/?page_id=369"},"modified":"2014-07-07T21:16:36","modified_gmt":"2014-07-07T21:16:36","slug":"evolution-of-myb","status":"publish","type":"page","link":"https:\/\/lipsick.su.domains\/?page_id=369","title":{"rendered":"Evolution of Myb"},"content":{"rendered":"

Three closely related Myb genes are present in vertebrate animals including mammals, birds, amphibians, and bony fish.\u00a0 In the laboratory mouse, c-Myb\/MYB is required for blood cell production in the embryo and for intestinal maintenance in adults, A-Myb\/MYBL1 is required for spermatogenesis and mammary gland proliferation, and B-Myb\/MYBL2 is required very early in embryonic development.\u00a0 The invertebrate sea urchin and fruit fly each have a single Myb gene most closely related to B-Myb\/MYBL2 of vertebrates.<\/span><\/p>\n

\"animal<\/a><\/p>\n

The DNA-binding domains of these Myb proteins of animals all contain three tandem repeats of ~50 amino acids each (blue boxes) located near the amino terminus (left end).\u00a0 In addition, all of these proteins contain a negative regulatory domain (green box) located near the carboxyl terminus (right end).\u00a0 The A-Myb and c-Myb proteins contain an evolutionarily conserved central transcriptional activation domain (red box) that is not present in B-Myb or the Myb proteins of invertebrates.\u00a0 The corresponding region of B-Myb has continued to evolve rapidly. These results suggest that A-Myb and c-Myb arose by two gene duplications (red circles) that occurred after the emergence of the vertebrate lineage.\u00a0 In support of this hypothesis, we have found that B-Myb, but neither A-Myb nor c-Myb, can complement the hemocyte (blood cell) defects in <\/span>Drosophila <\/span><\/span>larvae that lack a functional Myb gene.\u00a0\u00a0Surprisingly, the intensively studied nematode worm Caenorhabditis<\/span> elegans<\/em> lacks a closely related Myb gene.\u00a0 This gene appears to have been lost during the the evolution of nematodes, because simpler invertebrate animals including the sea anemone do have a Myb gene that is closely related to the Myb genes of vertebrate animals.
\n<\/span><\/p>\n

\"animal<\/a><\/p>\n

All green plants contain one or a few different genes encoding Myb proteins with a DNA-binding domain composed of three tandem repeats.\u00a0 In addition, flowering plant species each contain over a hundred different genes encoding Myb proteins with a DNA-binding domain containing only two tandem repeats.\u00a0 Cellular slime molds and some species of fungi also contain Myb proteins with a DNA-binding domain composed of three tandem repeats.<\/p>\n

\"eukaryotic<\/a><\/p>\n

More distantly related proteins containing one or more Myb repeats are present in all eukaryotes (organisms with nucleated cells).\u00a0 This larger family of Myb-related proteins include components of machines that remodel nucleosomes (SWI3 and ISWI), that covalently modify histone tails (ADA2 and NCoR), that regulate RNA polymerase III (TFIIIB”), and that bind telomeric DNA sequences (TRF1, TRF2, TAZ1, and RAP1).\u00a0 These more widely divergent Myb-related proteins are sometimes referred to collectively as “SANT domain proteins”.\u00a0 Thus far, Myb-related genes have not been found in prokaryotes (bacterial organisms that lack a cell nucleus).<\/p>\n","protected":false},"excerpt":{"rendered":"

Three closely related Myb genes are present in vertebrate animals including mammals, birds, amphibians, and bony fish.\u00a0 In the laboratory mouse, c-Myb\/MYB is required for blood cell production in the embryo and for intestinal maintenance in adults, A-Myb\/MYBL1 is required for spermatogenesis and mammary gland proliferation, and B-Myb\/MYBL2 is required very early in embryonic development.\u00a0 … Continue reading Evolution of Myb<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-369","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/lipsick.su.domains\/index.php?rest_route=\/wp\/v2\/pages\/369","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lipsick.su.domains\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/lipsick.su.domains\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/lipsick.su.domains\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lipsick.su.domains\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=369"}],"version-history":[{"count":6,"href":"https:\/\/lipsick.su.domains\/index.php?rest_route=\/wp\/v2\/pages\/369\/revisions"}],"predecessor-version":[{"id":495,"href":"https:\/\/lipsick.su.domains\/index.php?rest_route=\/wp\/v2\/pages\/369\/revisions\/495"}],"wp:attachment":[{"href":"https:\/\/lipsick.su.domains\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=369"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}