THE BOOROOLA FECUNDITY (FECB) GENE MAPS TO SHEEP CHROMOSOME-6

The Booroola (FecB) mutation in sheep is linked to markers from a region of syntenic homology to human chromosome HSA4q, but the chromosomal location in sheep has not been determined. Analysis of linkage in Booroola half-sib pedigrees and 17 full-sib families identified genetic linkage between platelet-derived growth factor receptor-alpha (PDGFRA) and alpha(s1)-casein (CSN1S1) at 12 cM (Z(max) = 9.14) and between PDGFRA and the microsatellite markers BM143 and OarHH55 (Z(max) = 6.28 and 3.83, respectively). The microsatellite markers OarAE101 and BM143 and genes from the linkage group (PDGFRA, SPP1, and EGF) were mapped in a partial sheep x hamster somatic cell hybrid panel. Ah markers identified bands specific to somatic cell hybrids containing the sheep chromosome t1 (rob6;24) or t1q (chromosome 6). In sheep the casein genes alpha(s1) (CSN1S1), alpha(s2) (CSN1SB), beta (CSN2), and K (CSN3) are tightly linked, and CSNP has been mapped to sheep chromosome 6q23-q31. We conclude that the Booroola mutation is located within a conserved syntenic group that maps to sheep chromosome 6. (C) 1994 Academic Press, Inc

SHEEP LINKAGE MAPPING - 19 LINKAGE GROUPS DERIVED FROM THE ANALYSIS OF PATERNAL HALF-SIB FAMILIES

Nineteen linkage groups containing a total of 52 markers have been identified in the sheep genome after typing large paternal half-sib families. The linkage groups range in size from 2 markers showing no recombination to a group containing 6 markers covering approximately 30 cM of the sheep genome. Thirteen of the groups have been assigned to a sheep chromosome. Three groups contain markers from bovine syntenic groups U2, U7 and U29, and one other group contains a marker that has been mapped only in humans. The remaining three groups are unassigned. This information will provide a useful foundation for a genetic linkage map of sheep

Sheep Linkage Mapping: Nineteen Linkage Groups Derived from the Analysis of Paternal Half-Sib Families

Nineteen linkage groups containing a total of 52 markers have been identified in the sheep genome after typing large paternal half-sib families. The linkage groups range in size from 2 markers showing no recombination to a group containing 6 markers covering approximately 30 cM of the sheep genome. Thirteen of the groups have been assigned to a sheep chromosome. Three groups contain markers from bovine syntenic groups U2, U7 and U29, and one other group contains a marker that has been mapped only in humans. The remaining three groups are unassigned. This information will provide a useful foundation for a genetic linkage map of sheep

Corticoadrenal activity regulates in rat betaine-homocysteine S-methyltransferase expression with opposites effects in liver and kidney

Betaine-homocysteine S-methyltransferase (BHMT) is an enzyme that converts homocysteine (Hcy) to methionine using betaine as a methyl donor. Betaine also acts as osmolyte in kidney medulla, protecting cells from high extracellular osmolarity. Hepatic BHMT expression is regulated by salt intake. Hormones, particularly corticosteroids, also regulate BHMT expression in rat liver. We investigated to know whether the corticoadrenal activity plays a role in kidney BHMT expression. BHMT activity in rat kidneys is several orders of magnitude lower than in rat livers and only restricted to the renal cortex. This study confirms that corticosteroids stimulate BHMT activity in the liver and, for the first time in an animal model, also up-regulate the BHMT gene expression. Besides, unlike the liver, corticosteroids in rat kidney down-regulate BHMT expression and activity. Given that the classical effect of adrenocortical activity on the kidney is associated with sodium and water re-absorption by the distal tubule leading to volume expansion, by promoting lesser use of betaine as a methyl donor, corticosteroids would preserve betaine for its other role as osmoprotectant against changes in the extracellular osmotic conditions. We conclude that corticosteroids are, at least in part, responsible for the inhibition of BHMT expression and activity in rat kidneys.Fil: Fridman, Osvaldo. Universidad Abierta Interamericana; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; ArgentinaFil: Morales, Analía Verónica. Universidad Abierta Interamericana; ArgentinaFil: Bortoni, Laura Egle. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; ArgentinaFil: Turk Noceto, Paula Cecilia. Universidad Abierta Interamericana; ArgentinaFil: Prieto, Elio A.. Universidad Abierta Interamericana; Argentin