摘要:

AbstractSequences of DNA that hybridize on Southern blots with cloned EcoR1 1.3 kb (ER1) of long interspersed repeated sequence (L1Md) of mouse have been examined in genomic DNA of neonatal mice, livers and brains of adult mice (3, 10, 27, and 30 mo old), and the solid myeloma tumor MOPC‐315. The isoschizomers Hpa II (CCGG ormCCGG) and Msp I (CCGG or CmCGG) were used to assess methylation. We found that the L1Md sequence is fully methylated in young animals but demethylated in myeloma. Demethylation of L1Md sequence also occurred in aged animals. By scanning the autoradiogram, we found that approximately 8% of the 104–105copies have been demethylated in 27‐mo‐ol

ISSN:0192-253X    

DOI:10.1002/dvg.1020070202

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

年代:1986

数据来源: WILEY

摘要:

AbstractK575is a temperature‐sensitive female sterile mutant which shows abnormal chorion structure and subnormal amounts of the major chorion proteins at the restrictive temperature. These phenotypes apparently result from a temperature‐sensitive defect in amplification. Both clusters of chorion genes are affected, indicating that the gene operates intr

ISSN:0192-253X    

DOI:10.1002/dvg.1020070203

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

年代:1986

数据来源: WILEY

摘要:

AbstractIn analyzing the in vitro pattern of protein synthesis by the fat body and ovaries of the Hawaiian speciesDrosophila grimshawi, we have found that the ovaries synthesize much more protein than the female fat body and that the majority of the synthesized proteins are retained by the ovarian tissues. In contrast, the fat body secretes most of the proteins into the culture medium. Vitellogenins are the major class of proteins synthesized and released into the medium by both tissues. The synthesis of the three vitellogenin proteins (V1, V2, V3,) is noncoordinate in the two tissues. Ovaries synthesize much more of the V2 protein, less V1and very little V3, whereas fat body synthesies more Vs1protein with lesser qu antities of the other two. The follicle cells were identified as the site of ovarian vitellogenin synthesis inD. grimshawi, confirming the findings inD. melanogaster.InD. grimshawi, the three vitellogenins are synthesized by the follicle cells in a noncoordinate and developmentally regulated manner. V2and V1are the predominant proteins at the onset of vitellogenesis (S8–9); their production peaks together with that of V3a few hours later (S10) and then decreases to quantitiesequalto that of V3 during early choriogenesis (S11). During active choriogenesis (S12), V2 and V1 cease to be synthesized, but V3 synthesis continues. The vitellogenins synthesized by the follicles in vitro are released into the medium and not incorporated into the oocyt

ISSN:0192-253X    

DOI:10.1002/dvg.1020070204

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

年代:1986

数据来源: WILEY

摘要:

AbstractWe have analyzed the expression of a series of developmentally regulated genes in theDictyostelium discoideumstrain JC‐5. This strain has been previously described as a temperature‐sensitive, cohesion‐defective derivative of FR17, itself a temporally deranged mutant of wild‐type NC‐4. At restrictive temperature (27°C), JC‐5 initially acquires EDTA‐resistant cell contacts but at the time of tip formation (12 hr) loses the ability to make specific cell‐cell associations and regresses to an amorphous mound of cells. We have found that genes preferentially expressed in either prespore or prestalk cells are expressed prior to the appearance of the cohesion defect in JC‐5; the specific cell contact system defective in this strain is necessary for neither the proper initiation nor maintenance of expression of either prespore of prestalk genes. We have also found, by use of anin vitrocell suspension system, that JC‐5 is temperature‐sensitive with respect to gene expression several hours before the defect in cell cohesion is observable. Our data suggest that the defect in JC‐5 is due to a specific lesion not in the late cohesion system but rather in a more general component that is required earlier in t

ISSN:0192-253X    

DOI:10.1002/dvg.1020070205

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe genetic factorSxrcauses sex reversal of chromosomally female (XX or XO) mice to phenotypic maleness by inducing development of testes that produce androgens. It has been considered that these sex‐reversed animals, called pseudomales, confirm the principle originally developed by Jost that adequate androgenization produces normal phenotypic maleness in mammals, irrespective of chromosomal sex. However, wepreviously discovered that the epididymis of sex‐reversed XX mice (pseudomales of genotype XXSxr) lacks EH 9 cells (epididymal head, cell type No. 9, the principal cell' of the initial segment). The purpose of the present study was to determine whether cell type EH 9 of XXSxrpseudomales is replaced by a principal cell of a different appearance, or whether the initial segment itself is actually absent. We made serial sections of entire epididymal heads and did microdissections to unravel the highly coiled epididymal duct. Using these two approaches, we studied the sequence of epididymal segments, and estimated lengths of the relevant portion of the epididymal duct; we found that the initial segment of XXSxrpseudomales is truly absent. This is the first report of a mutant genotype causing absence of a segment of the epididymis. The XXSxrmutant appears to be an exception to Jost's principle. This finding shows that, even in full androgenization, male phenotype may not always be independent of chromosomal

ISSN:0192-253X    

DOI:10.1002/dvg.1020070206

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

年代:1986

数据来源: WILEY

ISSN:0192-253X    

DOI:10.1002/dvg.1020070207

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

年代:1986

数据来源: WILEY

ISSN:0192-253X    

DOI:10.1002/dvg.1020070201

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

年代:1986

数据来源: WILEY