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G Blanck

Publications and source records attributed to G Blanck.

At least 37 records · Page 2Linked to original sources
PubMed1994

Retinoblastoma protein regulation of surface CD74 (invariant chain) expression in breast carcinoma cells.

The HLA class II genes encode heterodimeric cell surface proteins which bind peptide antigen recognized by T-cell receptors on CD4+ T-cells. The class II proteins are inducible by IFN-gamma, and this induction requires, or is strongly enhanced, by retinoblastoma protein (RB) in a series of breast carcinoma cell lines. Loading of peptide onto the class II protein appears to be regulated by CD74, which associates with class II during their transition to the endosomal compartment, where class II binds peptide. Class II proteins and CD74 are largely regulated in concert, provoking the question, is CD74 induction by IFN-gamma affected by RB? Results described here indicate that IFN-gamma induction of CD74 surface expression in a series of breast carcinoma lines is enhanced by RB, while RB has no effect on CD74 mRNA induction. Also, neither the class II nor the CD74 promoter regions are activated by RB in cotransfection experiments where RB activates the SV40 promoter.

Antigens, CD↗
PubMed1994

Evidence for retinoblastoma protein (RB) dependent and independent IFN-gamma responses: RB coordinately rescues IFN-gamma induction of MHC class II gene transcription in noninducible breast carcinoma cells.

The class II major histocompatibility (MHC) genes encode cell surface heterodimers that present processed antigen to CD4 positive T-cells. The class II genes are expressed constitutively on B-cells and can be induced by IFN-gamma on a variety of other cell types. Because the class II genes are aberrantly expressed on many mesenchymal tumors, which are frequently defective for the retinoblastoma tumor suppressor protein (RB), we investigated the role of RB in the regulation of HLA-DR and -DP. The RB defective breast carcinomas cell line, MDA-468-S4 (S4), as well as S4 subclones reconstituted with RB coding sequences under the control of a zinc inducible promoter, were treated with IFN-gamma and examined for DR and DP expression. Surface DR is not inducible in S4 cells, but inducibility is rescued by RB. DP is only slightly inducible in S4, but inducible to a much higher level in the RB positive subclones of S4. IFN-gamma induction of DR and DP mRNAs are correspondingly dependent on RB. IFN-gamma receptors are present on S4 cells, and the guanylate binding protein and ICAM-1 genes respond to IFN-gamma, ruling out the possibility that all IFN-gamma signal transduction pathways are defective in S4 cells. These data indicate RB regulates the coordinate response of class II genes to IFN-gamma. Possible roles for RB in this process are discussed, as well as the role of the class II-noninducible phenotype in tumor rejection.

Breast Neoplasms↗
PubMed1989

A new cluster of genes within the human major histocompatibility complex.

A 435-kilobase (kb) DNA segment, which is centromeric to HLA-B in the human major histocompatibility complex, was isolated by chromosome walking with overlapping cosmids. Within the cloned region, the genes for the tumor necrosis factors (TNFs) alpha and beta and HLA-B were 210 kb apart. The human homolog of a mouse gene, B144, was located next to TNF alpha. Moreover, the presence of additional genes was suggested by a large cluster of CpG islands. With cosmid probes, several distinct transcripts were detected in RNA samples from a variety of cell lines. Altogether, five novel genes were identified by isolation of corresponding complementary DNA clones. These "HLA-B-associated transcripts" (BATs) were mapped to different locations within a 160-kb region that includes the genes for TNF alpha and TNF beta. The presence of the genes for BAT1 and BAT5 in the vicinity of HLA-B again raises the question of which gene in this region determines susceptibility to ankylosing spondylitis.

Animals↗
PubMed1988

Molecular organization of the DQ subregion (DO-DX-DV-DQ) of the human MHC and its evolutionary implications.

An overlapping set of cosmid clones from the homozygous DR7 B lymphoblastoid cell line MANN linking the HLA-DO through -DQ subregions is described. This region encompasses 280 kb of DNA, including DQ alpha, DQ beta, DX alpha, DX beta, DO beta, and recently indentified L chain sequences termed DV beta. The orientation and grouping of the alpha- and beta-chains is comparable with an analogous murine class II subregion and also with the HLA-DR alpha and -DR beta chains, suggesting that the arrangement of the constituent genes of class II subregions predates the mouse/human divergence.

Biological Evolution↗
PubMed1988

Multiple insertions and tandem repeats of origin-minus simian virus 40 DNA in transformed rat and mouse cells.

Stable simian virus 40 (SV40) transformation requires integration and expression of the early region of the SV40 genome. We have examined the amount and state of integrated viral DNA of SV40-transformed NIH 3T3 mouse and F2408 rat fibroblast lines generated by transfection with either wild-type or origin-defective SV40 DNA. A functional SV40 replication origin was not required for multiple inserts and partial-repeat structures to form in NIH 3T3 mouse transformants. In contrast, partial repeats in F2408 rat transformants were rare when the SV40 replication origin was intact and not detected at all when it was defective.

Animals↗
PubMed1988

The contribution of ego psychology to understanding the process of termination in psychoanalysis and psychotherapy.

Ego psychology is presented as an integrated psychoanalytic developmental theory, including a theory of object relations. The process of termination is employed as one of the many possible illustrations of the usefulness of this theory. Termination is regarded as a process that pervades the treatment from the outset, rather than as the final phase of treatment only, because the treatment process, whether psychoanalysis or psychotherapy, includes continuous promotion of ever-increasing autonomy. Ideally, by the time termination proper takes place, maximum autonomy has been attained. To the definition of autonomy as intersystemic, involving relative independence of the ego from the drives (and from the super-ego), an object-relations dimension is added which extends that definition to include an intrasystemic consideration--namely, relative independence of the self-representation from the object representations. Especially in the treatment of the borderline conditions is the intrasystemic factor cogent because borderline states are characterized by varying degrees of incompletely differentiated self- and object representations. The objective, in the psychoanalysis of neurosis, where self- and object constancy already exist to a large degree, is ego autonomy in the intersystemic sense. In the psychotherapy of the borderline conditions, the objective is greater differentiation of the self-representation from the object representations.

Ego↗
PubMed1985

Two integrated partial repeats of simian virus 40 together code for a super-T antigen.

We determined that the coding sequence for a 100-kilodalton super-T antigen found in Simian virus 40 mouse transformants spanned two separate partial repeats of the viral genome. The downstream repeat contained a complete Simian virus 40 large-T-antigen gene, whereas the upstream repeat was a truncated copy of the same gene. When the repeats were separated by subcloning, the capacity to code for the super-T antigen was lost. A small insertion or deletion in the origin-control region which preceded the second repeat could also destroy the ability to code for the 100-kilodalton protein. Our data suggest that differential splicing between parts of two gene copies was responsible for the additional molecular weight of this super-T antigen.

Animals↗
PubMed1984

SV40 transformation of Swiss 3T3 cells can cause a stable reduction in the calcium requirement for growth.

A well-characterized SV40-transformed Swiss 3T3 line, SV101, and its revertants were tested for the ability to grow in reduced Ca++ (0.01 mM). Transformants and revertants did not differ from the parent 3T3 line in their Ca++ requirements. All three classes of cells grew less well in low Ca++ than in regular Ca++ (2.0 mM). SV40 transformants were then selected for the ability to grow in reduced Ca++. This new class of transformants was found to grow in 1% serum, grow in soft agarose, have a reorganized actin cytoskeleton, and express viral T antigens, as well as grow well in low Ca++. One of the selected clones was found to be T antigen-negative, yet was transformed in the serum, anchorage, actin, and Ca++ assays. It is possible that this clone was a spontaneous transformant. However, Southern blot analysis revealed the presence of integrated SV40 DNA. In addition, this analysis revealed the absence of an intact early region fragment, which codes for the viral T antigens. One explanation of this result may be that the mechanism of viral transformation for growth in low Ca++ involves viral-host DNA interactions that may not require a fully functional T antigen. In this case SV40 integration may be acting as a nonspecific cellular mutagen.

Animals↗
PubMed1984

DNase I sensitivity of integrated simian virus 40 DNA.

We undertook an analysis of integrated simian virus 40 (SV40) DNA to learn whether the DNase I-sensitive region is retained in the integrated array of mouse transformants. Our results indicate that full-length integrated SV40 chromatin retains a DNase I-hypersensitive region at the same point as in nonintegrated SV40 chromatin. Thus, the lack of a DNase I-hypersensitive region is not likely to be the reason for nonpermissivity of SV40 in mouse cells. In addition, results reported here indicate that a deletion of about 200 base pairs of DNA in the region of the DNase I-hypersensitive site severely reduces the sensitivity of integrated SV40 chromatin. This result is similar to a previously reported result obtained with deletion mutants of SV40 analyzed in the lytic cycle. It is the first report of a DNA lesion affecting DNase I hypersensitivity of a mammalian chromosome.

Animals↗
PubMed1984

Reacquisition of a functional early region by a mouse transformant containing only defective simian virus 40 DNA.

Viral DNA in simian virus 40-transformed mouse cells is capable of rearranging with passage. In this report, we show that such rearrangement can include an alteration in viral protein expression. SVT2, a simian virus 40-transformed mouse BALB/c 3T3 cell line, synthesizes only a super T antigen of molecular weight 100,000 without synthesizing the lytic-size large T or small t antigens with molecular weights of 94,000 and 17,000, respectively. Analyses of the integrated viral DNA revealed an early region of 4.4 kilobases instead of the lytic-size 2.7 kilobases. However, upon subcloning in either plastic or agarose or after being in culture for several passages, the appearance of lytic-size large T and small t antigens was detected. Concurrently, an early region of 2.7 kilobases, in addition to one of 4.4 kilobases, was observed.

Antigens, Viral, Tumor↗
PubMed1984

The complete oedipus complex.

The 'Complete Oedipus Complex' is shown to be a critical period in Spitz' sense of convergence of drive maturation with ego development. It is proposed that competence to venture into the heart of the oedipal conflict is acquired in the practising subphase of the separation-individuation process where traits such as venture-someness, courage, initiative and the like become part of the self representations. Also proposed is that tension between drive need and object relations need at the anal phase results in compromise that establishes a pattern for taming the drive because of object relations considerations. The so-called negative oedipal position is seen as a regression to a pre-oedipal level of object need that is tinged with sexual wishes carried back from the oedipal position. Finally, the waning of the Oedipus complex is regarded as another developmental thrust terminating in identification with and love for the parent of the same sex, with transfer of functions of the object representations to the self representations, which results in diminution of primary object need and frees the individual to make new libidinal connexions at adult levels of object need.

Ego↗
PubMed1983

Integration, loss, and reacquisition of defective viral DNA in SV40-transformed mouse cell lines.

We have examined the state of viral DNA in a set of SV40-transformed mouse cell lines. Using restriction enzymes which cut SV40 DNA in one place, we demonstrate that anchorage-independent SV40-transformed mouse cells commonly contain one or more detectable defective monomers of integrated viral DNA. The defective viral DNA in one of these cell lines, SV101, was extensively mapped using single and double enzyme digests. The results of this analysis indicate that SV101 contains nondefective viral DNA as well as defective viral DNA of the following sizes: 5.0, 4.3, 3.7, 3.4, and 1.5 kb. Three of these defective monomers (4.3, 3.7, and 1.5 kb) preserve the amino terminal exon of large T antigen, and two monomers (4.3, and 3.7 kb) preserve the little t coding region. Anchorage-dependent subclones of SV101 preferentially lose the defective viral DNA, while retaining an intact SV40 early region and the ability to express lytic-sized large and small T antigens. Despite a considerable amount of viral DNA rearrangement which accompanies subcloning, anchorage-independent subclones of SV101 retain defective viral DNA, especially the 4.3- and 3.7-kb monomers. Also, when an anchorage-independent subclone is selected from an anchorage-dependent revertant of SV101, it reacquires defective viral DNA, although of a size not seen in SV101. We conclude that defective viral DNA plays a role in generating the anchorage-independent phenotype. In earlier studies, we have reported that anchorage-transformed mouse lines contain a variant (100kDa) T antigen. The possible role of defective viral DNA in generating this T antigen is discussed.

Animals↗
PubMed1983

Pre-crisis mouse cells show strain-specific covariation in the amount of 54-kilodalton phosphoprotein and in susceptibility to transformation by simian virus 40.

We have used several inbred mouse strains to examine the role of the 54-kilodalton (kDa) cellular phosphoprotein in transformation by the papovavirus simian virus 40. We have measured the endogenous 54-kDa phosphoprotein in cells obtained from these inbred mouse strains. To study the effect of passage, cell cultures were measured for amount of the 54-kDa phosphoprotein at the 2nd and 12th passages. In the absence of any transforming agent, the amount of endogenous 54-kDa phosphoprotein in early pre-crisis mouse cells varied in a strain-specific way. Transformation frequency varied coordinately with endogenous 54-kDa expression. Mouse strains whose cells produced a high level of endogenous 54-kDa phosphoprotein on passage did not further increase its expression after simian virus 40 transformation.

Animals↗
PubMed1983

A frameshift mutation affecting the carboxyl terminus of the simian virus 40 large tumor antigen results in a replication- and transformation-defective virus.

We have constructed a frameshift mutation in the simian virus 40 early region using a novel method of oligonucleotide-directed mutagenesis. The mutated DNA specifies an 84,000-dalton large tumor antigen that consists of approximately equal to 75,000 daltons encoded by the wild-type reading frame and 9,000 daltons, by the alternative reading frame (wild-type large tumor antigen is approximately equal to 82,000 daltons). The frameshifted carboxyl terminus of the protein bears a strong similarity to the same region of polyoma virus middle-sized tumor antigen. We have found that the mutant DNA is unable to replicate when introduced into permissive monkey cells and incapable of transforming nonpermissive mouse cells.

Amino Acid Sequence↗
PubMed1983

A functional simian virus 40 origin of replication is required for the generation of a super T antigen with a molecular weight of 100,000 in transformed mouse cells.

We used two recombinant plasmids, one containing wild-type simian virus 40 DNA (pSVR1) and the other containing a simian virus 40 genome with a defective origin of replication (pSVR1-origin-minus) to transfect NIH3T3 cells. Quantitation of T-antigen synthesis by indirect immunofluorescence at 48 h after transfection with either DNA revealed the same percentage of T-positive nuclei. The transformation frequencies observed were also similar with both plasmids. Immunoprecipitation of [35S]methionine-labeled cell extracts showed the expected 94,000-dalton (94K) T and 17K t antigens in all clones examined. In pSVR1-generated transformants, a 100K super T antigen was also detected. Transformants isolated from pSVR1-origin-minus transfection, however, never expressed this 100K super T antigen, and some of these clones originally also showed greatly reduced levels of 94K T antigen. However, after growth in culture for several generations, the levels of 94K T antigen synthesis in these underproducer clones were dramatically increased. A direct correlation between the amounts of T antigen synthesized and the ability to grow independently of anchorage was observed. The mechanism which brings about increasing levels of T-antigen synthesis in some of the clones is not clear, but it appears not to be due to changes in either the copy number or the methylation pattern of the integrated simian virus 40 DNA.

Animals↗