摘要:

AbstractLysosomal acid hydrolase expression during preimplantation mouse embryogenesis has proved useful in estimating when mRNA transcription commences during this period. Previous work from this laboratory has shown that α‐galactosidase and β‐glucuronidase undergo 50‐ to 100‐fold increases in activity between the two‐cell stage and the blastocyst stage [1, 2]. Here we show that β‐galactosidase activity levels undergo a similar change. We also demonstrate that mouse strains with theBgl‐shallele produce cleavage stage embryos with 2–4‐fold higher activity levels than strains with theBgl‐sdallele.Bglhas been shown to control β‐galactosidase levels in adult mouse tissues [3]. Unfertilized egg β‐galactosidase levels are also regulated byBgl, but loci distant fromBglmodify egg expression. The distant sites are not observed to act during cleavage. Hybrid embryos (Bgl‐sd/h) show intermediate activity levels to the parental types. The timing of the deviation of hybrid embryo β‐galactosidase activity levels from maternal‐type activity levels is used to estimate when transcription of genes governin

ISSN:0192-253X    

DOI:10.1002/dvg.1020020102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractIn P. tetraurelia each cell is determined to express only one of the two complementary mating types,OandE. This determination is under cytoplasmic control and seems to be achieved only by the commitment or noncommitment to the expression of mating typeE. All the previously known mutations affecting the differentiation of mating type prevent the expression of theEmating type (O‐restricted mutations) without affecting thedeterminationprocess. AnE‐restricted mutation was obtained:mtFE. Its phenotypic properties indicate that the mutation affects the determination process itself. When anOcell becomesmtFE/mtFEit acquires theEmating type and anE‐determining cytoplasm. We propose that this constitutive determination for theEmating type is due to the inefficiency of a factor which is normally active in anOcell. This factor would act like a repressor and stabilize theEfunctions under an inactive

ISSN:0192-253X    

DOI:10.1002/dvg.1020020103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractThemtFEmutation isolated in Paramecium tetraurelia affects mating type differentiation, trichocyst excretion, and viability. Its effect on mating type has already been shown to correspond to a restriction to theEmating type interpreted by an inefficiency of nuclearO‐determining factors. In this paper we study the other two phenotypic characteristics whose hereditary transmission displays two unusual features. (1) In crosses between a wild‐type strain and the mutant strain, the mutant characteristics do not reappear in F2 in the wild‐type cytoplasmic lineage but only in F3 after the homozygous clones have undergone an additional nuclear reorganization. (2) Some F2 wild‐type clones, in the mutant cytoplasmic lineage, retain some of the phenotypic characteristics of the mutant. We propose that themtFgene product plays a role in the control of several macronuclearly differentiated fu

ISSN:0192-253X    

DOI:10.1002/dvg.1020020104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractEmbryos homozygous for the recessive lethal gene, micromelia‐Abbott, develop a severe form of micromelia, a parrot‐like beak, and hemorrhagic skin. Feather development is also retarded. The reduction in length of the long bones of the leg can be traced to their cartilaginous stage Quantitative analysis of sulfated proteoglycan (PGS), a major macromolecular component of cartilage matrix, reveals that mutant tibiae, femora, and sterna contain significantly less uronic acid per μg of DNA than normal rudiments, indicating reduced accumulation of PGS in the mutant. Incorporation of radioactive precursors into cartilage PGS is severely reduced in relatively early developmental stages of a particular organ, but this reduction becomes less severe in cartilage taken from the same rudiment at a later developmental stage. Analysis of the sedimentation rate of PGS in sucrose gradients reveals no difference between normal and mutant in all cartilaginous types at all ages. These results suggest that the quantity and not the quality of PGS is affected in this mutant. The observation that the addition of para‐nitrophenyl‐β‐D‐xyloside to the culture medium can stimulate glycosaminoglycan synthesis to normal levels is interpreted to mean that the reduced levels of PGS may be the result of a reduced availability of the xylosylated protein bac

ISSN:0192-253X    

DOI:10.1002/dvg.1020020105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractMutations at the bithorax locus transform anterior haltere tissue into anterior wing. These transformations could in principle be due to the mutations altering either the expression or cell heredity functions of determination. I have studied two alleles of the bithorax locusbx3andbx34eusing disc culture techniques and found that both produce their transformations by altering the expression of the determined state. I have also found that the expression of the temperature‐sensitive allele,bx34e, can be altered by temperature shifts during the culture period. Evidence has been obtained that suggests that such changes in expression do not require growth or cell divisio

ISSN:0192-253X    

DOI:10.1002/dvg.1020020106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractIn a study of the regulation of enzyme patterns in imaginal discs the aldehyde oxidase pattern was determined for some homoeotic mutations of D. melanogaster. Earlier indications that suggested that this pattern follows the determinitive state of compartments within imaginal discs were confirmed by the aldehyde oxidase (AO) pattern of both the wing and haltere discs fromen1; bx3, en1; pbx, anden1; bx3pbxlarvae and the antennal discs fromAntp73bandssalarvae.We additionally analyzed whether AO activity depended on the determinative state of an entire compartment or was expressed autonomously in clones. Homozygous engrailed clones were induced by mitotic recombination. From the AO clones found in normally negative areas of the posterior compartment it was concluded that enzyme activity depended upon the determinative state of the cells and was not a function of the compartment as a whole.The results are described with reference to a scheme in which compartmental and subcompartmental selector genes are thought to determine a binary code on which AO patterns depend.

ISSN:0192-253X    

DOI:10.1002/dvg.1020020107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractThe tissue specificity of a proposed cis‐acting temporal locus (Adh‐3t), which regulates alcohol dehydrogenase C2(ADH‐C2) activity in mouse reproductive tissue extracts, has been examined in C5 7BL/6J, SM/J, F1(SM/J × C5 7BL/6J) mice as well as in progeny of an (F1[SM/J × C5 7BL/6J] × C5 7BL/6J) back‐cross. Electrophoretic variants for ADH‐C2, previously used to localize the gene (Adh‐3) encoding this enzyme on chromosome 3, enabled the relative parental contributions to ADH‐C2phenotype in F1and backcross mouse tissues to be determined. These analyses demonstrated that (1) stomach, kidney, lung, adrenals, seminal vesicles, epididymis, uterus, and ovary ADH‐C2is encoded by a single locus (Adh‐3); Adh‐3t is differentially active in various tissues, eg, lung exhibits no apparent activity whereas the temporal locus is fully active in seminal vesicles; (3) Adh‐3t is probably differentically active in different cells of some tissues, eg, adrenals. Specific activity profiles of stomach and epididymal ADH‐C2during the neonatal development of C5 7BL/6J, SM/J, and F1(SM/J × C5 7BL/6J) male mice supported the proposal for a cis‐acting temporal locus for this enzyme. Genetic analyses examining segregation of Adh‐3 and Adh‐3t among backcross progeny suggested that these are distinct but closely linked loci, since one recombinant among 256 progeny was observed. Linkage data of Adh‐3 with Va (varitint‐waddler) and de (droopy ear) was also obtained, which suggested that Adh‐3 is loca

ISSN:0192-253X    

DOI:10.1002/dvg.1020020108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractThe anti‐mitotic herbicide isopropyl N‐(3‐chlorophenyl) carbamate (CIPC) prevents the growth of amoebae of Dictyostelium discoideum without killing the cells for a period of time equivalent to one generation. During in‐hibition, amoebae accumulate in prophase and metaphase of mitosis. After removal of CIPC, they continue through mitosis and then divide.The addition of CIPC to amoebae under starvation conditions prevents aggregation and concomitant cell elongation. The cells, however, do not lose their ability to adhere to a surface, and they remain viable. When CIPC is added to amoebae which have formed streams, it leads to the disintegration of streams into small clusters of cells and to a loss of cell elongation.Post‐aggregation stages of development can be inhibited by CIPC at the mound, slug, or Mexican hat stages. Slugs break apart into distinct aggregates.Mutants resistant to CIPC can be obtained easily. Among these mutants, many become temperature sensititive for growth (27°C) or development (27°C or 15.5°C). Others show various abnormalities at the normal temperature (22°C). Most mutants are cross resistant to the microtubule inhibitors nocodazole and thiabendazole, and some are also resistant to CIPC durin

ISSN:0192-253X    

DOI:10.1002/dvg.1020020109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractThe complete developmental program of glycerol‐3‐phosphate dehydrogenase in wild type Drosophila is described with respect to activity, isozyme expression, and GPDH‐specific CRM. Variants of this developmental program have been isolated from natural populations which affect the rate of accumulation of only the GPDH‐3 isozyme in both the larval and adult stages of development. This activity variation segregates as a single gene which is tightly linked to the structural element on Chromosome II, exhibits cis‐control, and is tissue specific in expression. This gene meets all the criteria for temporal regulat

ISSN:0192-253X    

DOI:10.1002/dvg.1020020110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY

摘要:

AbstractNew, improved media and procedures for making rat chimeric embryos and culturing them in vitro have been developed. We have produced 27 rat chimeras: 20 males and 7 females. This ratio of males to females is consistent with that seen in mouse chimeras, suggesting that rat sex chimeras develop as phenotypic males. By aggregating embryos containing appropriate genetic markers for pigment cell differentiation, it is possible to produce chimeras that elucidate the site of action of the hooded gene. The coat color patterns of black ↔ black hooded chimeras display a white belly spot. In black ↔ albino hooded chimeras, small patches of white hair appear on the head and a large white spot occurs on the belly. Black ↔ agouti hooded chimeras display both agouti and nonagouti pigmentation over the entire surface of the chimera. These animals are fully pigmented with no white spots. In black ↔ albino non‐hooded chimeras, rather small irregular patches of black and white hairs are distributed throughout the pelage. Histological examination of sections of hair follicles obtained from the white areas in the head of black ↔ albino hooded chimeras revealed amelanotic melanocytes. On the other hand, hair bulbs from the white belly spots do not contain any such melanocytes. Thus the white hairs of the head are due to the presence of albino melanocytes, but the white hairs of the belly are due to the total absence of melanocytes. All these observations are consistent with the conclusion that the hooded gene acts within melanoblasts, probably to retard their migration from the neural crest and/or to prevent their entrance into the hair follicles of the white areas of

ISSN:0192-253X    

DOI:10.1002/dvg.1020020111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1981

数据来源: WILEY