RESUMO
The DNA copy-number variant (CNV) is a kind of segments of DNA ranging from 1 kb to 3 Mb that is present in a variable number of copies.CNVs widely distribute across the human genome,and dramatically increases genetic diversity.In recent years,researches have found that most CNVs are closely related to complex diseases.If a cancer gene is directly encompassed or overlapped by a CNV,it may lead to activation of oncogenes or inactivation of tumor suppressor genes,and finally results in tumorigenesis.CNVs can affect gene expression,phenotype differences and phenotypic adaptations by changing gene dosages and gene activities,and then sequentially lead to tumor or any other genetic dieases.Investigating CNVs is apparently helpful for studing chromosome recombination,genomic evolution,gene expression and the pathogenesis of multiple complex diseases especially tumor.
RESUMO
In the present study, comparison have been made between two kinds of double labelling methods; single side labelling and both sides labelling. To make the different groups be comparable, all sections were continuously cut from the same specimen and all labelling processes were carried out at the same ti- me. The groups were divided as follows: A, one side anti-?-amylase labelling and one side antitrypsin labelling; B, single side labelling of anti-?-amylase and antitrypsin; C, one incubation with anti-?-amylase, followed by two incu- bations with protein A-gold (PAG) complexes of varied size, C1: 7nm and 20nm, C2: 10nm and 20nm, C3: 20nm and 7nm; D, single side labelling of anti- ?-amylase and an unrelated antiserum (antichathepsin D), applying free protein A between two labellings; E, as C, but with free protein A between two PAG incubations; F, as control. Group A and B showed that the two labelling me- thods had almost the same sensitivity.Group C indicated that the interaction of single side labelling were resulted from the combination of the second PAG with the free Fc region of the first antiserum. To decrease the interaction, it was necessary for the second PAG to be much larger than the first one.Group D de- monstrated that the interaction between the second antiserum and the first PAG was very feeble. Group E proved that free protein A could completely prevent the interaction of single side labelling method. The both sides labelling method avoids interaction, but mistakes resulting from the ultrastructural differences on two sides of the sections may happen. Which method to be selected is dependent upon what to be labelled.