Lin-4 Essay

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micro RNAs (miRNAs) are small non-coding RNas with approximately 20 nucleotides in length. They control gene expression during post-transcription by binding to 3’ or 5’ untranslated regions of the target mRNAs, which prevent translation, or mRNA degradation. The first miRNA known as Lin-4 was discovered in the nematode C. elegans in 1993 by a joint effort of Victor Ambros’s and Gary Ruvkun’s laboratories (Bartel DR 2004; Lee RC 1993). In C. elegans, the temporal developmental pattern of all larval stages were tightly controlled by the heterochromin genes. Among these genes is Lin-4, which was discovered by the isolation of a null mutation that caused a failure during temporal development (Horvitz HR 1980; Chalfie M 1981). Lin-4 mutant animals were missing some adult structures, were unable to lay eggs, and suffered from developmental defects. This study concluded that Lin-4 is essential …show more content…

In 1987, Fergusson et al., (from Hortitz’s lab) found that a mutation of the Lin-14 ¬gene caused the opposite phenotype of the Lin-4 mutant worms (Lee RC 2004, Ferguson EL1987). These studies suggested that Lin-4 could be the negative regulator of Lin-14 (Lee RC 2004). Following these findings, Ambros and his colleagues, Roslind Lee and Rhonda Feinbaum, found a 700bp fragment encoded in the Lin-4 gene which did not have the conventional start and stop codonsAs a result of their subsequent investigation, they generated a mutation in the putative ORFs; however, the Lin-4 function remained unchanged. Ambros then concluded that Lin-4 contained no coding region for protein (Lee RC 1993 and 2004). In addition, they found two very small Lin-4 transcripts with only 61 and 22 bp lengths (Lee RC 1993). While

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