title: Complete budding and asymmetric division of primitive model cells to produce daughter vesicles with different interior and membrane compositions.
abstract: Asymmetric cell division is common in biology and plays critical roles in differentiation and development. Unicellular organisms are often used as model systems for understanding the origins and consequences of asymmetry during cell division. Although basic as compared to mammalian cells, these are already quite complex. We report complete budding and asymmetric fission of very simple nonliving model cells to produce daughter vesicles that are chemically distinct in both interior and membrane compositions. Our model cells are based on giant lipid vesicles (GVs, 10-30 μm) encapsulating a polyethylene glycol (PEG)/dextran aqueous two-phase system (ATPS) as a crowded and compartmentalized cytoplasm mimic. Ternary lipid compositions were used to provide coexisting micrometer-scale liquid disordered (L(d)) and liquid ordered (L(o)) domains in the membranes. ATPS-containing vesicles formed buds when sucrose was added externally to provide increased osmotic pressure, such that they became not only morphologically asymmetric but also asymmetric in both their interior and their membrane compositions. Further increases in osmolality drove formation of two chemically distinct daughter vesicles, which were in some cases connected by a lipid nanotube (complete budding), and in others were not (fission). In all cases, separation occurred at the aqueous-aqueous phase boundary, such that one daughter vesicle contained the PEG-rich aqueous phase and the other contained the dextran-rich aqueous phase. PEGylated lipids localized in the L(o) domain resulted in this membrane domain preferentially coating the PEG-rich bud prior to division, and subsequently the PEG-rich daughter vesicle. Varying the mole ratio of lipids resulted in excess surface area of L(o) or L(d) membrane domains such that, upon division, this excess portion was inherited by one of the daughter vesicles. In some cases, a second "generation" of aqueous phase separation and budding could be induced in these daughter vesicles. Asymmetric fission of a simple self-assembled model cell, with production of daughter vesicles that harbored different protein concentrations and lipid compositions, is an example of the seemingly complex behavior possible for simple molecular assemblies. These compartmentalized and asymmetrically dividing ATPS-containing GVs could serve as a test bed for investigating possible roles for spatial and organizational cues in asymmetric cell division and inheritance.
authors: Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors: Meghan
authors: M
authors: Andes-Koback
authors: Christine D
authors: CD
authors: Keating
references: J Phys Chem B. 2007 Aug 30;111(34):10155-9
references: 17685641
references: Phys Rev Lett. 2006 Feb 3;96(4):048104
references: 16486900
references: Biophys Chem. 2009 Jul;143(1-2):106-9
references: 19442430
references: Annu Rev Microbiol. 2010;64:391-408
references: 20825353
references: Annu Rev Phys Chem. 2004;55:613-49
references: 15117264
references: Wiley Interdiscip Rev Nanomed Nanobiotechnol. 2010 May-Jun;2(3):260-76
references: 20166114
references: Dev Cell. 2005 Dec;9(6):791-804
references: 16326391
references: Biophys J. 1993 Apr;64(4):1133-8
references: 19431884
references: Science. 1996 Aug 16;273(5277):933-5
references: 8688071
references: Phys Rev Lett. 2004 Oct 8;93(15):158104
references: 15524946
references: Proc Natl Acad Sci U S A. 2002 Apr 16;99(8):5394-9
references: 11959994
references: Langmuir. 2007 Jun 19;23(13):7148-54
references: 17516666
references: Genes Dev. 2009 Dec 1;23(23):2675-99
references: 19952104
references: Science. 2005 Oct 14;310(5746):310-4
references: 16224022
references: J Phys Condens Matter. 2006 Jul 19;18(28):S1151-76
references: 21690835
references: J Biosci Bioeng. 2001;92(6):590-3
references: 16233152
references: Biochim Biophys Acta. 2009 Feb;1788(2):567-74
references: 19027713
references: Langmuir. 2005 Feb 15;21(4):1230-7
references: 15697265
references: Biophys J. 1993 Oct;65(4):1396-403
references: 8274633
references: Proc Natl Acad Sci U S A. 2010 Apr 20;107(16):7208-13
references: 20368457
references: Proc Natl Acad Sci U S A. 2011 Mar 22;108(12):4731-6
references: 21383120
references: Int Rev Cytol. 2000;192:171-87
references: 10553279
references: Biophys J. 2004 May;86(5):2910-22
references: 15111407
references: Langmuir. 2005 Aug 30;21(18):8478-86
references: 16114960
references: J Am Chem Soc. 2002 Nov 13;124(45):13374-5
references: 12418876
references: J Am Chem Soc. 2008 Sep 17;130(37):12252-3
references: 18712871
references: Biophys J. 1996 Dec;71(6):3242-50
references: 8968594
references: Microbiol Mol Biol Rev. 2005 Dec;69(4):544-64
references: 16339735
references: Phys Rev Lett. 2001 Feb 5;86(6):1138-41
references: 11178029
references: Nat Rev Microbiol. 2008 Sep;6(9):681-91
references: 18679172
references: Proc Natl Acad Sci U S A. 2004 Dec 21;101(51):17669-74
references: 15591347
references: Biomol Eng. 2001 Oct 31;18(4):143-77
references: 11576871
references: J Am Chem Soc. 2010 Jan 13;132(1):195-201
references: 20000420
references: Annu Rev Cell Dev Biol. 2009;25:671-99
references: 19575640
references: Chemphyschem. 2009 Nov 9;10(16):2769-76
references: 19774545
references: Nature. 2003 Oct 23;425(6960):821-4
references: 14574408
references: Chembiochem. 2010 May 3;11(7):848-65
references: 20336703
references: Langmuir. 2008 Dec 2;24(23):13565-71
references: 18980360
references: Annu Rev Anal Chem (Palo Alto Calif). 2008;1:801-32
references: 20636098
references: Biochim Biophys Acta. 2009 Jan;1788(1):53-63
references: 18930706
references: Biophys J. 1999 Oct;77(4):1992-2002
references: 10512819
references: Proc Natl Acad Sci U S A. 2005 Feb 15;102(7):2402-7
references: 15701694
references: Science. 2009 Jun 26;324(5935):1729-32
references: 19460965
references: Curr Opin Biotechnol. 2007 Aug;18(4):333-40
references: 17709236
references: Phys Rev Lett. 2002 Dec 23;89(26):268101
references: 12484857
references: Biophys J. 2004 Apr;86(4):2179-87
references: 15041658
references: Biophys J. 2008 Jun;94(12):4725-36
references: 18339739
references: Biochim Biophys Acta. 2005 Dec 30;1746(3):172-85
references: 16043244
references: Langmuir. 2010 Aug 17;26(16):13195-200
references: 20695558
references: J Phys Condens Matter. 2010 Feb 17;22(6):062101
references: 21389358
references: Science. 2004 Jan 23;303(5657):495-9
references: 14645856
references: Cell. 2010 Jan 22;140(2):257-67
references: 20141839
references: Langmuir. 2004 Oct 26;20(22):9526-34
references: 15491182
references: Trends Biochem Sci. 2001 Oct;26(10):597-604
references: 11590012
references: Biophys J. 2005 Aug;89(2):1067-80
references: 15894634
references: Science. 2008 Apr 4;320(5872):103-6
references: 18388293
references: Chem Phys Lipids. 2005 Jul;136(1):55-66
references: 15927174
references: Langmuir. 2007 Jan 16;23(2):720-8
references: 17209626
references: Phys Rev A. 1991 Jul 15;44(2):1182-1202
references: 9906067
references: J Am Chem Soc. 2009 Apr 22;131(15):5705-13
references: 19323552
references: Proc Natl Acad Sci U S A. 2011 Jan 18;108(3):1052-7
references: 21191097
references: J Am Chem Soc. 2009 Jul 1;131(25):9094-9
references: 19496598
references: Nature. 1998 Jul 30;394(6692):459-62
references: 9697768
references: J Am Chem Soc. 2008 Jan 16;130(2):756-62
references: 18092782
references: J Am Chem Soc. 2009 Oct 14;131(40):14158-9
references: 19775107
references: Chembiochem. 2002 May 03;3(5):409-17
references: 12007174
references: Biophys J. 1997 May;72(5):2042-55
references: 9129807
references: Biophys J. 1982 Apr;38(1):29-37
references: 7074197
references: EMBO J. 2005 Apr 20;24(8):1537-45
references: 15791208
references: Chem Phys Lipids. 2004 Apr;129(1):53-62
references: 14998727
references: Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics. 1996 Mar;53(3):2670-2683
references: 9964554
references: Curr Opin Chem Biol. 2004 Dec;8(6):660-4
references: 15556412
references: Langmuir. 2010 Apr 20;26(8):5697-705
references: 19928785
references: Nat Rev Mol Cell Biol. 2010 Dec;11(12):849-60
references: 21102610
references: Chembiochem. 2008 Oct 13;9(15):2403-10
references: 18785673
references: J Am Chem Soc. 2008 Jun 11;130(23):7400-6
references: 18479139
references: Curr Biol. 2006 Apr 18;16(8):R269-71
references: 16631567
references: Trends Plant Sci. 2000 Apr;5(4):174-82
references: 10740299
references: Nat Cell Biol. 2007 Jan;9(1):7-14
references: 17199125
references: FEBS Lett. 2010 May 3;584(9):1685-93
references: 20036659
references: Curr Opin Biotechnol. 2009 Aug;20(4):492-7
references: 19729295
references: Chem Commun (Camb). 2010 Jun 7;46(21):3639-53
references: 20442914
references: Phys Rev Lett. 2009 Dec 4;103(23):238103
references: 20366179
references: Cell. 1992 Jan 24;68(2):237-55
references: 1733500
references: J Biol Phys. 2002 Dec;28(4):733-44
references: 23345810
references: J Cell Biol. 2001 Oct 15;155(2):193-200
references: 11604418
references: Int Rev Cytol. 2000;192:155-70
references: 10553278
references: Phys Rev Lett. 1994 Sep 5;73(10):1392-1395
references: 10056781
references: Annu Rev Biophys. 2008;37:375-97
references: 18573087
references: Proc Natl Acad Sci U S A. 2009 Apr 7;106(14):5622-6
references: 19304798
references: Proc Natl Acad Sci U S A. 2005 Apr 26;102(17):5920-5
references: 15788532
references: J Am Chem Soc. 2004 Jul 21;126(28):8594-5
references: 15250679
references: Langmuir. 2008 Apr 15;24(8):3686-9
references: 18336048
references: Nat Rev Mol Cell Biol. 2006 Jun;7(6):456-62
references: 16625153
references: Soft Matter. 2007 Apr 24;3(5):587-595
references: 32900022
references: J Phys Chem B. 2007 Feb 22;111(7):1775-85
references: 17266364