GENETIC DISSECTION OF lin-11 REGULATION IN DIFFERENTIATION OF C. elegans AMPHID SENSORY NEURONS

Abstract

<p>The expression of <em>lin-11</em> is regulated by enhancers located upstream from, as well as within, <em>lin-11</em> intronic sequences. Multiple regulatory inputs control the spatiotemporal expression pattern of <em>lin-11</em>. To better understand that process, we have investigated these regulatory enhancers by dissecting two of the biggest intronic sequences of <em>lin-11</em>: intron 3 and intron 7. Using microscopy, we show that the expression of intron 3 is required in ten head sensory neurons and that the expression of intron 7 is required in two head neurons. The truncation of intron 7 revealed that its regulatory sequence may be located within its narrow 98 base pairs (bp) region. We used bioinformatics to predict which putative transcription factor(s) may regulate AVG expression. Using a hypersensitive RNAi mutant strain, <em>eri-1; lin-15b,</em> we tested forty putative transcription factors and quantitated the number of animals in which the molecular marker <em>lin-11::GFP</em> expression is knockdown in AVG interneurons.</p> <p>Using electrotactic behavioral analysis we show that the speed of<em> lin-11</em> null allele, n389, is reduced by almost 50%, when compared to that of the wildtype animals, due to amphid sensory neuronal deformities. We determine which conserved domains of <em>lin-11</em> are required for the proper development of the neuronal and vulval cells via microinjection rescue experiments.</p> <p>We sequenced eleven <em>lin-11</em> alleles to determine which conserved domains are affected and the role of each of these domains in the development of vulval and neuronal cells. Our findings suggest that all <em>lin-11</em> conserved domains are required for proper vulval cell differentiation as well as for proper development of the amphid sensory neurons. Finally, using tissue specific markers we label vulval cells in <em>lin-11</em> mutants to show that those cells are defective, as judged by the lack of fate-specific markers in the vulval cells.</p>