Clinical Implications caused by the agenesis of the RectusAbdominal Muscle’s (MRA) inferior venter

The rectus abdominal muscle is part of the anterior abdominal wall, having three to six bellies. In only oneof the 106 dissections already made in the “Faculdade de Ciências Médicas de Minas Gerais” AnatomyLaboratory was found a male cadaver who did not have inferior venter of this muscle bilaterally. Instead, at theleft side, was found a tendon that measured 5.5 cm laterally and 12 cm medially, and at the right side, therewas the same variation with a 15.5 cm length tendon, rising in the upper branch of the pubis and crest pubis.Despite being a rare variation, individuals who have showed it have increased potential for physiological andsurgical complications, in case they need interventions using inferior rectus abdominis muscle venter’s snips.

Influence of the polymorphisms of the alpha-major regulatory element HS-40 on in vitro gene expression

The α-MRE is the major regulatory element responsible for the expression of human α-like globin genes. It is genetically polymorphic, and six different haplotypes, named A to F, have been identified in some population groups from Europe, Africa and Asia and in native Indians from two Brazilian Indian tribes. Most of the mutations that constitute the α-MRE haplotypes are located in flanking sequences of binding sites for nuclear factors. To our knowledge, there are no experimental studies evaluating whether such variability may influence the α-MRE enhancer activity. We analyzed and compared the expression of luciferase of nine constructs containing different α-MRE elements as enhancers. Genomic DNA samples from controls with A (wild-type α-MRE) and B haplotypes were used to generate C-F haplotypes by site-directed mutagenesis. In addition, three other elements containing only the G→A polymorphism at positions +130, +199, and +209, separately, were also tested. The different α-MRE elements were amplified and cloned into a plasmid containing the luciferase reporter gene and the SV40 promoter and used to transiently transfect K562 cells. A noticeable reduction in luciferase expression was observed with all constructs compared with the A haplotype. The greatest reductions occurred with the F haplotype (+96, C→A) and the isolated polymorphism +209, both located near the SP1 protein-binding sites believed not to be active in vivo. These are the first analyses of α-MRE polymorphisms on gene expression and demonstrate that these single nucleotide polymorphisms, although outside the binding sites for nuclear factors, are able to influence in vitro gene expression.