Components of the SWI/SNF Complex Are Required for Asymmetric Cell Division in C. elegans  Hitoshi Sawa, Hiroko Kouike, Hideyuki Okano  Molecular Cell  Volume 6, Issue 3, Pages 617-624 (September 2000) DOI: 10.1016/S1097-2765(00)00060-5

Figure 1 Abnormal T Cell Lineages in psa-1 and psa-4 Mutants at the L1 Stage psa-4 animals were grown at 22.5°C. psa-1 embryos were grown at 15°C for 6 hr, then shifted to 22.5°C or 25°C. The numbers of animals that showed the lineages are indicated below the diagrams. The fates of cells (“hyp.” for hypodermal; “neural”) were determined by nuclear morphology (Experimental Procedures). Asterisks indicate phasmid socket cells in wild type. We did not necessarily follow the subsequent divisions after cells showed an apparent neural morphology except that we confirmed that they did not produce any hypodermal cells. Molecular Cell 2000 6, 617-624DOI: (10.1016/S1097-2765(00)00060-5)

Figure 2 psa-1 and psa-4 Are Required during the T Cell Division Temperature downshift (A and C) and upshift (B and D) experiments with psa-1 (A and B) and psa-4 (C and D). Newly laid eggs of appropriate genotypes were grown at 15°C (B and D), 22.5°C (C), or 15°C for 6 hr followed by a shift to 22.5°C (A). L1 larvae were quickly staged by observing the Q and T cells under the Nomarski optics at room temperature (22°–23°C). The larvae were quickly transferred to plates which had been incubated at 15°C (A and C) or 22.5°C (B and D). The plates were incubated at 15°C (A and C) or 22.5°C (B and D) for about 1 day, when the larvae were examined for the Psa phenotype. The shift procedures took less than 2 min. Timing of temperature shifts is indicated on the left of each diagram. “Before the T cell division” indicates that temperature was shifted after or during the Q cell division but before the T cell division, “at hatching” indicates that temperature was shifted within 30 min after hatching, “just after the T cell division” indicates that temperature was shifted after the T cell division when the T cell on the other side was dividing, “n” represents the number of sides examined. Molecular Cell 2000 6, 617-624DOI: (10.1016/S1097-2765(00)00060-5)

Figure 3 Molecular Cloning of psa-1 and psa-4 (A and C) (Top) Genetic maps of psa-1 (A) and psa-4 (C) loci with cosmids and YAC clones in the regions indicated. (Bottom) Structures of the genes and constructs. Bold lines and boxes indicate genomic and exon sequences, respectively. 5′ of the genes is to the right in (A) and to the left in (C). Coding regions are shaded. All of the indicated constructs rescued the mutant phenotypes. (B and D) Domain structures of PSA-1 (B), PSA-4 (D), and their homologs. Each conserved domain is shaded, and the percentage of identity with the corresponding domain of the PSA-1 or PSA-4 proteins is indicated. The total lengths of the proteins are indicated on the right. Molecular Cell 2000 6, 617-624DOI: (10.1016/S1097-2765(00)00060-5)

Figure 4 psa-1 and psa-4 Are Expressed Ubiquitously Expression of psa-1::GFP (A–D) and psa-4::GFP (E–H). Anterior is to the left and ventral is to the bottom. (A and E) Whole L1 animals examined by epifluorescent microscopy. (B–D) and (F–H) Confocal images of the tail region in L1 animals. (C) and (G) are Nomarski images of the same regions as (D) and (H), respectively. The T cells are in telophase in (C–D) and (G–H). Molecular Cell 2000 6, 617-624DOI: (10.1016/S1097-2765(00)00060-5)

Figure 5 Three Models for the Regulation of Asymmetric T Cell Division Left and right sides represent the T.a and T.p cell, respectively. Horizontal lines represent the promoter region of the DNA. Large and small circles represent the SWI/SNF complex and transcription factors, respectively. Open circles represent the active complex or active proteins. Black circles represent the inactive complex or inactive proteins. (A) Wnt signaling activates transcription factors that are recruited by SWI/SNF. (B) Wnt signaling negatively regulates an ASH1-like protein that blocks recruitment of SWI/SNF. (C) Wnt signaling directly activates SWI/SNF in the T.p cell. SWI/SNF is inactive in T.a. Molecular Cell 2000 6, 617-624DOI: (10.1016/S1097-2765(00)00060-5)