[Analysis of the genetic variability of complement component C4 by real-time PCR].

Recent findings revealed that the repetitions of long DNA sequences comprising the sequence of different genes (CNV - copy-number variations) are very common in the human genome. A well-known example for this type of variations is the "RCCX-module" that implies the tandem duplication of four genes - RP, 21-hydroxylase, complement component C4 and tenascin X - in a haplotype block. Only the C4 gene is active in each module, besides, each module may contain C4A or C4B gene encoding the two isoforms of complement C4.

Real-time PCR quantification of human complement C4A and C4B genes.

Background: The fourth component of human complement (C4), an essential factor of the innate immunity, is represented as two isoforms (C4A and C4B) in the genome. Although these genes differ only in 5 nucleotides, the encoded C4A and C4B proteins are functionally different. Based on phenotypic determination, unbalanced production of C4A and C4B is associated with several diseases, such as systemic lupus erythematosus, type 1 diabetes, several autoimmune diseases, moreover with higher morbidity and mortality of myocardial infarction and increased susceptibility for bacterial infections.

Heterologous movement protein strongly modifies the infection phenotype of cucumber mosaic virus.

A hybrid virus (CMVcymMP) constructed by replacing the movement protein (MP) of cucumber mosaic cucumovirus (CMV) with that of cymbidium ringspot tombusvirus (CymRSV) was viable and could efficiently spread both cell to cell and long distance in host plants. The hybrid virus was able to move cell to cell in the absence of functional CP, whereas CP-deficient CMV was restricted to single inoculated cells. In several Chenopodium and Nicotiana species, the symptom phenotype of the hybrid virus infection was clearly determined by the foreign MP gene.