[The spotted sterile male--a new mutation of dominant spotting on the mouse chromosome 5]. / Spotted sterile male--novaia mutatsiia dominantnoi piatnistosti v 5-oi khromosome myshi.

Spotted sterile male - a new mutation in mice is described (tentative symbol Ssm). White spotting on the belly, legs and tail as well as sterility in heterozygous males Ssm/+ of the B10.M strain are caused by autosomal semidominant gene Ssm. The gene is localized on the 5 chromosome: the frequency of recombination between Ssm and go is 13.6 +/- 1.6%; Ssm is closely linked to Wv. The diheterozygotes Ssm+/+Wv are darkeyed white sterile mice. The deficiency of spermatogenic epithelium cells, emptyness of seminiferous tubules as well as interstitial tissue overgrowing occurred in the testis in sterile males Ssm/+ of B10.M. The fertile hybrid males Ssm/+ are obtained in outcrossing of females Ssm/+ of B10.M with males of YT/Y, CBA/CaY, DBA/2JY, A.CA/Y strains.

[Clonal analysis of the development of the pigment epithelium of the eye in chimeric or/or----AKR mice]. / Klonalnyi analiz razvitiia pigmentnogo épiteliia glaza u khimernykh myshei or/or----AKR.

The development of cell clones was studied in the retinal pigment epithelium of chimaeric mice or/or----AKR. The clonal analysis suggests that on the 13th day of gestation the cells in the retinal pigment epithelium are distributed almost randomly while in the adults they are grouped in small coherent clones. In the retinal pigment epithelium the AKR cell predominated over the or/or cells. The interaction of mutant and normal clones during the eye development leads, in most cases, to the normalization of eyes in chimaeras. Cases of microphthalmia and asymmetry in distribution of clones suggest irregular and random distribution of these clones in the embryo.

[Variation in the expressivity of the ocular retardation gene in mice]. / Variatsiia ékspressivnosti gena ocular retardation u myshi.

Variation in the expressivity was studied of the gene for ocular retardation (or) in mice. It is shown that the gene or suppresses with a high expressivity the growth of the optic vesicle in homozygotes, this resulting in anophthalmia and microphthalmia with aphakia. In cases of low expressivity, the gene or inhibits the growth of retina anlage, this leading to microphthalmia with a cataract of the lens. Variation in the expressivity of the gene or is due to an influence of modifier genes.

[Distribution of melanocytes in the dorsal skin of genetic mouse chimeras]. / Raspredelenie melanotsitov v dorzal'noi chasti kozhi geneticheski khimernykh myshei.

Chimeras were obtained by aggregating two embryos from inbred mice (C57BL/Mib), C57BL/Mib mice, and outbred albino mice (c/c). It was shown that C57BL/Mib AKP chimeras had unbalanced pigment distribution with a higher proportion of AKR melanocytes in the posterior coat, while C57BL/Mib c/c chimeras had unbalanced pigment distribution with a higher proportion of C57BL/Mib melanocytes in the posterior coat. This observation can be explained, provided the differences in the migration rate of the three melanocyte populations from the neural crest are controlled genetically.

[Coat pigmentation and effect of the ocular retardation gene in the eye of chimeras between or/or and AKR mice]. / Pigmentatsiia sherstnogo pokrova i deistvie gena ocular retardation v glazakh khimernykh myshei, poluchennykh sliianiem or/or i AKR zarodyshei.

Twenty-five chimeric adult mice were obtained by aggregating 8-cell embryos of or/or and +/+ genotypes (AKR mice), according to the Tarkovsky and Mints method. The coat color and pigmentary epithelium of the eyes were evidence of chimerism. The coat colour of chimeras varied from a small white to a remarkable gray. The weight of the newborn chimeric mice did not differ from normal. The gene or in homozygotes suppressed the retinal anlage. It was noted that variability of the eye size was dependent on the number of or/or cells in the populations that formed the eyes in chimeras or/or in equilibrium AKR. In 18 animals the eye size did not differ from normal. The pigmentary epithelium of the eyes contained from 32 to 40% or or/or cells. Seven chimeras showed microphthalmos. Asymmetric eye abnormality was recorded in three cases. The pigmentary epithelium of such eyes contained from 63 to 84% or or/or cells.

[Effect of maternal genotype on the rate of preimplantation development in mice]. / Vliiani genotipa materi na skorost' predimplantasionnogo razvitiia myshi.

The genetic control of the rate of preimplantation development was studied in the mouse embryos. The number of cells in the embryo and the percentage of embryos at the blastocyst stage were determined on the 3.5 day of pregnancy. The experiments were carried out with CBA, A/He, C57Bl/Mib mice and mice homozygous by the mutant genes white (Miwh), fidget (fi) and ocular retardation (or), congenic with the inbred C57Bl/Mib mice. Contrasting differences were found between C57Bl/Mib and fi/fi mice. The rate of development of the morphologically normal C57Bl/Mib and fi/fi and F1 embryo was shown to depend on the maternal genotype, rather than on the paternal one. The effect of maternal genotype of the rate of preimplantation development was related to differences in the time of beginning of the cleavage. The rate of cleavage is similar for the C57Bl/Mib, fi/fi and F1 embryos.

[Development of microphthalmos in Mi wh/mi fi/fi and Mi wh/mi or/or mice]. / Razvitie mikroftal'mii u myshei Mi wh/mi fi/fi i Mi wh/mi or/or.

Eye development has been studied in 10-16-day-old embryos and newborn mice, genotypes Miwh/mi fi/fi, Miwh/mi or/or, Miwh/mi, or/or, fi/fi and wild-type (+/+) (normal mice from the inbred strain C57Bl/Mib). It has been demonstrated that the mitotic index of the primordial retina of embryos Miwh/mi fi/fi and Miwh/mi or/or does not differ from that of fi/fi and or/or embryos. Genes fi and or manifest their effects in Miwh/mi fi/fi and Miwh/mi or/or embryos, decreasing the mitotic index of the primordial retina. Owing the effects manifested by the genes fi and or in Miwh/mi fi/fi and Miwh/mi or/or embryos it is possible to assume that the nearer the activity of ectomesenchyme approaches the normal, the greater the effects of the genes controlling the development of the eye vesicle and the retina anlage.

[Osteopetrosis in mice caused by ectomesenchymal lesions]. / Osteopetroz u myshi, obuslovlennyi porazheniem ektomezenkhimy.

Pathogenesis of osteopetrosis in mice homozygotic for microphthalmia (symbol mi) mutant gene has been studied. Heparin concentration in the blood of mi/mi mice was demonstrated to be 10 times as little as the normal. Administration of different doses of heparin (1, 5, 10 per g of body weight) at different intervals (2--20, 10--20 and 20--25 days including) of their postnatal development causes partial or complete normalization in the construction of the central part of diaphysis of tubular bones. The number of heparin-secreting mast cells, derivatives of the neural crest is less than normal. Osteopetrosis in mi/mi mice is an integral part of the complex syndrom produced by the damage of neural crest cells.

[Study of autonomy of action of white gene in allophenic mice]. / I sledovanie avtonomnosti deistviia gena white u allofennoi myshi.

An allophenic mouse and three allophenic embryos were obtained by aggregating 8-cell-embryos of Miwh/Miwh and +/+ genotypes. The coat colour and pigment epithelium of the eyes indicated chimerism. Melanoblasts of genotype Miwh/Miwh were lost during the embryonic development. Variations of coat colour in a chimeric mouse were due to the interaction of normal melanocytes with the surrounding dermal cells which consisted of clones of Miwh/Miwh or +/+ genotypes and a mixture of both. Certain differences between the right (chimeric) and left (normal) eye development and a greater rate of normal clones growth were observed in the allophenic mouse. Pigmentation of the eyes of two allophenic embryos was less than normal. This indicated the autonomy of gene white action in mice.

[Activation of parathyroid hormone by heparin in vitro]. / Aktivatsiia paratireoidnogo gormona geparinom in vitro

Heparin proved to be essential component in bone resorption. In vitro heparin activated the effects of parathyroid hormone in respect to bone resorption, but heparin alone was incapable of causing the resorption.

Interaction of the ectomesenchyme and optic vesicle in mice.

We investigated eye development in embryos at the 17, 24, and 31 somite-pair stages homozygous for the two genes white (Mi-wh) and fidget (fi) (Mi-wh/Mi-whfi/fi), single homozygotes (fi/fi and Mi-wh/Mi-wh), and normal mice (the inbred C57 BL/Mib strain). The fi gene retards optic-vesicle growth, while the Mi-wh gene inhibits ectomesenchyme migration. It was shown that the mitotic index of the optic-vesicle wall and the retinal rudiment was considerably higher in Mi-wh/Mi-whfi/fi embryos than in fi/fi embryos and lower than in Mi-wh/Mi-wh and +/+ embryos. Ectomesenchyme affected by the white gene stimulated optic-vesicle growth, to some extent suppressing the effect of the fidget gene. The stimulation of optic-vesicle growth in the double homozygotes led to intensified induction of the lens placode. This indicates that the ectomesenchyme affects the optic rudiment at the optic-vesicle stage.

[Influence of parathyroid hormone and heparin on tooth development in mice homozygous for the microphthalmia mutation]. / Vliianie paratireoidnogo gormona i geparina na razvitie zubov u myshei, gomozigotnykh po mutatsii microphthalmia

In mice, homozygous by microphthalmia (mi/mi) gene the disturbance of dental development was due to defects in dental pulp and to the absence of bone resorpion. Administration of heparin or parathyroid hormone stimulated dental eruption in mi/mi mice. Following combined action of heparin and parathyroid hormone the number of erupted teeth was practically the same as after the action of heparin alone. Possibly the level of heparin is insufficient, but secretion of parathyroid hormone is unimpaired in mi/mi mice.