P element transposition and targeted manipulation of the Drosophila genome.
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Animals↗
Biomedical subjects
J W Sentry
Publications and source records attributed to J W Sentry.
Expression of actin and myosin genes during PC12 cell differentiation.
We have measured the accumulation of transcripts for myosin and actin during NGF induced differentiation of PC12 cells. Beta (beta) and gamma (gamma) actin and myosin light chains (MLC) 2 and 3 show different patterns of expression, with transient elevations in gene expression one day after NGF addition. This elevation occurs earlier than that of neurite outgrowth, neurofilament protein (NF68) (16) and Thy-1 glycoprotein gene expression. These results suggest differing mechanisms of control of actin and myosin expression, together with a varying function and relationship between them during NGF-induced neurite differentiation.
Actin Cytoskeleton↗
An element with long terminal repeats and its variant arrangements in the genome of Lilium henryi.
A 9.35 kbp element with long terminal direct repeats (LTRs) of 2.4 kbp has been characterized from the large genome of Lilium henryi. The organization of the element, named del, was examined in 20 fragments from a genomic DNA library constructed using phage EMBL3. Five fragments apparently contained full 9.35 kbp elements while in 11 del was recovered in part. Two clones carried tandem arrangements of del, with single LTRs and internal sequences alternating, and one insert contained a solo LTR. Evidence suggests that these arrangements, which can arise by unequal crossing over, have a genomic rather than a cloning origin. Finally, one cloned fragment had a complex del arrangement yet to be fully defined. Limited sequencing of five LTRs (from a full del, a tandem arrangement and a solo LTR) indicates that the consensus termini are 5'TGT...ACA3', with del sequences flanked by a 5 bp tandem repeat. Thus del shares properties with retrotransposons such as the copia family of Drosophila and Ty of yeast. However with more than 13,000 copies per genome it seems del has been amplified more than is usual for such elements.
Base Sequence↗
Plant retrotransposon from Lilium henryi is related to Ty3 of yeast and the gypsy group of Drosophila.
The lily retrotransposon del 1-46 is 9345 base pairs (bp) long. It has long terminal repeats (LTRs) of 2406 bp (left) and 2415 bp (right), which differ in sequence by 1.4%. Sequences similar to those involved in priming DNA synthesis in retroviruses occur in the internal region. Near the left LTR is a sequence complementary to 18 residues at the 3' end of methionine initiator tRNA of three plant species, and a run of 12 purines occurs close to the right LTR. One internal reading frame of del 1-46 has relatively few stop codons. The 1462-codon product from this frame has motifs, in N to C terminus order, corresponding to those identified with RNA binding, protease, reverse transcriptase, RNase H, and integrase functions in retroviruses and certain other retrotransposons. Amino acid sequence comparisons of three conserved pol regions show del to be closely related to the Ty3 retrotransposon of yeast (37-40% identity). del is also related to the gypsy group of Drosophila (17.6, 297, gypsy/mdg4, and 412), showing closer identity with their reverse transcriptase (32-38%) and RNase H (36-45%) domains than with their integrase domain (21-26%). It is proposed that a gypsy group ancestor exchanged the integrase region with a more distantly related element since its divergence from a del/Ty3 common ancestor. The occurrence of related retrotransposons in three different kingdoms (plants, animals, and fungi) strongly implies their horizontal transmission in recent evolutionary time.
Amino Acid Sequence↗