We have studied the transport of the Uukuniemi virus membrane glycoproteins in baby hamster kidney and chick embryo cells by using a temperature-sensitive mutant (tsl2). Uukuniemi virus assembles in the Golgi complex, where both glycoproteins Gl and G2 and nbcleocapsid protein N accumulate (E. Kuismanen, B.

Trisomy 12 mosaicism (44 per cent) was detected prenatally in cultured amniocytes. A cordocentesis was performed to confirm the result. Only normal cells were found in the fetal blood sample. The fetus was estimated to be at a low risk of having a chromosomal abnormality and the pregnancy continued. Eight days after birth, a congenital heart defect was detected in the child. Several dysmorphic features were also evident. Further karyotyping of different tissues revealed normal blood and urinary cells but trisomic cells in the placenta (100 per cent) and in skin fibroblasts (25 per cent). The child died at 5 weeks of age. In this case, the fetal blood sample failed to reveal the real chromosome constitution of the fetus.

SUMMARYWith the aim of isolating temperature-sensitive (ts) mutants defective in virus maturation or glycoprotein transport, Uukuniemi virus, a bunyavirus, was mutagenized with N-methyl-N'-nitro-N-nitrosoguanidine. Out of 13 initial clones unable to grow at 39 °C (non-permissive temperature), five mutants which grew to titres above 107 p.f.u./ml at 32 °C (permissive temperature) were selected for further studies. The mutants fell into two coinciding recombination-complementation groups. Three group I mutants (ts7, 8 and 12) and two group II mutants (ts6 and 11) synthesized all three RNA segments and were able to form the corresponding nucleoproteins at 39 °C. Thus, members of these two recombination groups had a RNA-positive phenotype. All five mutants showed immunofluorescence when cells were stained at 39 °C using a doublestaining technique employing monoclonal antibodies against the glycoproteins G 1 or G2, and polyclonal antibodies against the nucleoprotein, N. We have previously shown that in cells infected with wild-type virus both the G1/G2 and the N proteins accumulate in the Golgi complex, the site of virus maturation. In cells infected with tsl2, accumulation of G1 and G2, but not N protein, was observed in the Golgi complex at 39 °C. The N protein was found evenly scattered in the cytoplasm, suggesting lack of interaction between the G1/G2 and N proteins. With ts6 and 11, G1 and G2 appeared to accumulate and aggregate in the endoplasmic reticulum (ER) at 39 °C. The location of the N protein coincided with that of the aggregated glycoproteins, suggesting that the N protein interacted with G 1/G2 already in the ER.

In infected BHK21 cells, the glycoproteins G1 and G2 of a temperature‐sensitive mutant (ts12) of Uukuniemi virus (UUK) accumulate at 39 degrees C in the Golgi complex (GC) causing an expansion and vacuolization of this organelle. We have studied whether such an altered Golgi complex can carry out the glycosylation and transport to the plasma membrane (PM) of the Semliki Forest virus (SFV) glycoproteins in double‐infected cells. Double‐immunofluorescence staining showed that approximately 90% of the cells became infected with both viruses. Almost the same final yield of infectious SFV was obtained from double‐infected cells as from cells infected with SFV alone. The rate of transport from the endoplasmic reticulum (ER) via the GC to the plasma membrane of the SFV glycoproteins was analysed by immunofluorescence, surface radioimmunoassay and pulse‐chase labeling followed by immunoprecipitation, endoglycosidase H digestion and SDS‐PAGE. The results showed that: the SFV glycoproteins were readily transported to the cell surface in double‐infected cells, whereas the UUK glycoproteins were retained in the GC; the transport to the PM was retarded by approximately 20 min, due to a delay between the ER and the central Golgi; E1 of SFV appeared at the PM in a sialylated form. These results indicate that the morphologically altered GC had retained its functional integrity to glycosylate and transport plasma membrane glycoproteins.

A 3-year-old girl has a de novo deletion of 11q21-22.3. The patient was studied because of minor anomalies, disproportionate short stature, and developmental delay. The deletion was first detected by conventional cytogenetic analysis and defined further by using chromosome 11-specific YAC clones by fluorescent in situ hybridization (FISH) on metaphase chromosomes. Three YAC clones, 11H7, 4A5, and IH4, were lacking from one of the patient's chromosome 11. Trigonocepahly, hypertelorism, apparently low-set ears, mild renal abnormality, and delay in speech development found in our patient are similar findings in other published interstitial deletion cases. Our study shows that a molecular cytogenetic approach is useful in defining the specific location and the extent of an interstitial deletion in cytogenetically difficult areas such as 11q.