Françoise Haguenau

A quantitative electron microscopic study of the virus particles found in cells infected with Rous sarcoma virus

Abstract The presence of particles similar in morphology to avian sarcoma leukosis viruses has been confirmed in 17 cloned lines of nonproducing (NP) cells which have been infected with Rous sarcoma virus. A quantitative study with the electron microscope indicated that, on the average, the number of virus particles in NP cells was about 1.5% of what is usually found in cells infected with Rous-associated virus and about 3% of what is found in Rous virus-producing cells. There was a significant variation in the number of particles among the NP lines examined.

A Quantitative Autoradiographic Study of Nucleolus-Associated RNA and DNA Synthesis During the Eclipse Phase in Rous Sarcoma Virus-Infected Chicken Fibroblasts

Functional and morphologic differences between the sensitivity of nucleoli of Rous sarcoma virus-transformed cells and that of newly infected cells to the action of actinomycin D (AD) have been demonstrated by quantitative light and electron microscope autoradiography and utilized to investigate the function of the nucleolus in the early stages of infection. After a pulse exposure to low doses of AD, increased RNA synthesis is induced within 80 minutes in the fibrillar portion of the nucleolus by infection. A concomitant increase in the retention of tritiated AD in the nucleolus and a quantitative redistribution of intranuclear and cytoplasmic DNA label are interpreted as evidence for a virus-induced amplification of the binding sites of AD in nucleolar chromatin.

Charles Oberling (1895-1960): a herald of modern oncology.

Charles Oberling was one of the most renowned pathologists of his generation. He combined scientific excellence with an engaging personality and a broad cultural background. These traits served to attract both young students and renowned scientists to his side. He created a cancer research center unique for its time, where many different scientific and medical disciplines were brought together. He was one of the first physicians to suggest that viruses played an etiologic role in human carcinogenesis, with many of his writings in this field showing amazing prescience. He fought boldly for the role of viruses as a cause of human cancer, even though few of his peers agreed at the time. It is appropiate to remember him now, as cancer researchers have demonstrated that many different types of viruses may be implicated in human malignancies. Recent reviews on the matter [1] illustrate just how timely a topic viral carcinogenesis has become. Viruses play a role, acting as a trigger, in the origin of 15% to 20% of all cancers. Although viral infection is a necessary prerequisite, it alone is insufficient, since many cofactors may be involved at various stages of carcinogenesis, just as Oberling had predicted. The prevailing scientific atmosphere when Oberling postulated that viruses may cause cancer was less than receptive. Even Peyton Rous, the first investigator to show in 1910 that a virus could indeed induce a cancer, did not pursue his work at the time because it was received with total disbelief and even sarcasm. Only a man of strong character could win such an intellectual battle. It required scientific competence, unerring intuition, determination, and both the art to convince and the power to accomplish. Oberling was endowed with all of these virtues. However, such qualities alone are not enough; good fortune is also needed. Oberling was lucky to encounter 2 great scientific minds, Pierre Masson and Amedee Borrel, early in his training. Their guidance and support played a major role in determining the course of his career. Oberlings personal and professional life unfolded with the logic and harmony inherent to his personality, being punctuated by a series of distinct and exciting episodes. He was born in 1895 in the town of Metz, in the province of Lorraine, which had been annexed by Germany after the Franco-Prussian War of 1870 together with Alsace. His family came from Berlingen, a village in the vicinity of Phalsbourg. His

Nucleolar ultrastructure and transcription of preribosomal RNA in Rous Sarcoma Virus-Transformed Chick Embryo Fibroblasts Treated With α-Amanitin

Uninfected and Rous sarcoma virus (RSV)-transformed chick embryo fibroblasts (CEF) were exposed to various concentrations of alpha-amanitin for different lengths of time. At a concentration of 4 micrograms alpha-amanitin/ml, RSV-transformed cells were shown to maintain a normal rate of transcription of all classes of RNA, whereas in uninfected cells transcription was reduced to a very low level. These observations cannot be accounted for by a difference in the penetration rate of alpha-amanitin through the plasma membrane. Investigation of the ultrastructure showed that the degree of nucleolar fragmentation induced by alpha-amanitin was comparable in both types of cells. Persistence of transcription with concomitant nucleolar fragmentation in alpha-amanitin-treated RSV-transformed CEF is not in accord with the hypothesis that nucleolar integrity is required for preribosomal RNA transcription.